The Laws involved in performing a Bris on Shabbos
1. In what scenarios is a child to be circumcised on Shabbos?
The circumcision of an infant is to be performed on the eighth day after birth even if it falls on Shabbos. If however it is past the child’s eighth day and the child has still not been circumcised for whatever reason, then the circumcision may not be done on Shabbos.
A child who was born during twilight: A child who was born during Bein Hashmashos of either Erev Shabbos or Motzaei Shabbos is not to be circumcised on Shabbos. Even if the child stuck out majority of his head during Bein Hashmashos, even though it was only fully removed after nightfall, nevertheless it is considered as if he was born during Bein Hashmashos and the circumcision may not be done on Shabbos. [For this reason special heed must be taken to verify the exact time the baby’s head has protruded in case of a birth taking place near the time of Bein Hashmashos of Erev Shabbos or Shabbos! Nevertheless, unless known otherwise, we do not assume the head came out much time prior to the body and we thus go in accordance to when the baby was taken out. However other Poskim rule it is always considered a doubt as to whether the head exited during Bein Hashmashos if she was in active labor during Bein Hashmashos and then gave birth at the beginning of the night.]
A premature baby: A premature baby who is medically able to be circumcised on his eighth day, may be circumcised on Shabbos. If however the child’s hair or nails are not fully developed and it is questionable whether the child was born in its eighth month, and certainly if one knows that it was born in the eighth month, then it is better to abstain from circumcising this child on Shabbos. [This applies even today, despite the fact that most premature babies of this kind will live to term.] Nevertheless some are accustomed even in such a case to circumcise the child on Shabbos. If the child has fully developed hair and nails, or it does not but one knows for certain that it is a ninth or seventh month baby, then it is to be circumcised on Shabbos. [Practically based on standard medical advice it is suggested to always wait until the 36-37th week prior to circumcising, even if the child is Halachicly allowed to be circumcised on Shabbos.]
Ben Mumar: A child born from a father who is an apostate Jew is to be circumcised on Shabbos if it coincides with his 8th day, if the mother is not an apostate Jew. [Likewise if the father is not an apostate while the mother is, the child is to be circumcised on Shabbos.] If however both the mother and the father are apostate Jews it is disputed amongst Poskim whether one may circumcise the child on Shabbos. [Practically, the custom is to circumcise all Jewish children on Shabbos if it coincides with their 8th day irrelevant of their parent’s religious affiliation.]
Mother Jewish, father not: It is disputed amongst Poskim whether a child who was born from a gentile father may be circumcised on Shabbos even if it coincides with his 8th day.
Father Jewish, mother not: A child whose mother is not Jewish is forbidden to be circumcised on Shabbos [even if it coincides with the child’s 8th day and the father wants to convert him].
Mamzeir: A Mamzeir is to be circumcised on Shabbos if it coincides with his 8th day.
The following children may not be circumcised on Shabbos even if they were born the previous Shabbos:
- A child born with C-Section.
- A child born circumcised.
- An Androgenus.
- A child born with two foreskins
- A child born with two Gidim,
- A child which converted after the birth, before the eighth day.
- Father of child is not Jewish-dispute if may be circumcised.
- Mother of child is not Jewish
May one circumcise the child of an unorthodox couple on Shabbos if doing so will lead to unnecessary desecration of Shabbos?
Other Poskim however rule that if one is certain that unnecessary Shabbos desecration will occur due to the circumcision, then it is to be delayed until the next day. If however due to one’s refusal an unorthodox Mohel will be hired in one’s place to perform the Bris on Shabbos, then he may agree to do so. In any event [according to this latter opinion] one is to try to influence the parents to delay the Bris under different pretexts, such as the child is too yellow and reasons of the like.
Must a Mohel agree to travel away from home to do a Shabbos Milah?
Some Poskim rule the Mohel is obligated to travel to the area of the child in order to perform a Bris. Others however rule there is no obligation to do so. This especially applies today that it is possible for the baby to come to the Mohel’s area for Shabbos. Likewise some Poskim rule there is no obligation to do so for the child of a non-orthodox couple.
One who follows Rabbeinu Tam regarding Motzaei Shabbos, how is he to follow regarding a child born after sunset?
If a child was born on Shabbos with use of a vacuum is he to be circumcised on his 8th day which coincides with Shabbos?
Is an IVF or AI baby to be circumcised on his 8th day which coincides with Shabbos?
2. Actions that may be performed for the child when a Bris is performed on Shabbos:
- Medical treatment to the area: One may place a bandage or poultice on the area of circumcision. Likewise all other medical treatments may be done to the area of circumcision. Nevertheless initially one is required to prepare all the medical treatments before Shabbos [if their preparation involves transgressing Shabbos, even Rabbinically]. Thus all ointments which require preparation are to be prepared before Shabbos. If one did not prepare the medicines before Shabbos then one may do so on Shabbos with an irregularity. If one is unable to prepare the medicines on Shabbos using an irregularity then it is forbidden to prepare them on Shabbos [even if doing so involves only a Rabbinical transgression]. It is forbidden to prepare the medicine in such a case even if this will cause the circumcision to need to be delayed until the next day. If however the child was already circumcised then all matters may be done to treat the child, even if they could have been done before Shabbos.
- Removing pieces of the foreskin after the circumcision: After the circumcision it is permitted, if necessary, to cut off any remaining pieces of the foreskin if those pieces refrain the Mitzvah from being fulfilled. However those pieces of skin which do not refrain the Mitzvah’s fulfillment, even though they are initially required to be removed, may not be cut on Shabbos once the Mohel has removed his hand from the area after the initial circumcision. Prior however to removing his hand from the area of circumcision it is permitted to fix and cut even these pieces of skin.
3. Machshireiy Milah/Transgressions involved in preparing for the circumcision:
Only the act of circumcision itself overrides Shabbos, while all other matters which are done to prepare for the circumcision may not be done on Shabbos if they involve any Shabbos prohibition, even of Rabbinical nature. Thus all the forbidden preparations for the circumcision must be done from before Shabbos. This includes:
- Sharpening the blade
- Bringing the knife to the area of the circumcision must be done before Shabbos if it involves passing an area in which carrying is forbidden, whether Biblically or Rabbinically.
- Preparation of medicines, as explained above.
If a person did not do the above before Shabbos: If a forbidden action was not taken care of from before Shabbos, it remains forbidden to do so on Shabbos even if doing so involves a mere Rabbinical prohibition, and even if this will cause the circumcision to be delayed until the next day. This applies even if it was beyond one’s control that the above actions were not fulfilled before Shabbos. Likewise even if the necessary preparations were fulfilled before Shabbos but the items got lost [or damaged] and new one’s are required it nevertheless remains forbidden.
Asking a gentile to do one of the forbidden preparations: One may ask a gentile to perform a Rabbinically forbidden action needed for the circumcision. Furthermore, if absolutely necessary to the point that lack of doing so will require delaying the circumcision until the next day, one may even ask a gentile to perform a Biblically forbidden act needed for the circumcision.
Asking a gentile to carry the child to Shul: It is disputed whether one may ask a gentile to carry the infant from his house to Shul if the area does not have an Eiruv. Practically those which are lenient are to do as follows: The gentile is to take the child out from his house into the public domain. The child is then to be handed to a Jew which in turn hands it to another Jew within his 4 cubit radius and so on and so forth until the child reaches near the entrance of the Shul. The gentile then takes the child and carries him into the Shul.
4. Bathing the infant:
Today that it is no longer viewed as a medical necessity to bathe a circumcised child, it remains forbidden to do so to the child the same way as is forbidden for an adult. Nevertheless if one sees that it is necessary to be done for medical reasons, and lack of doing so can endanger the child, then one may desecrate Shabbos for the infant just as is the law in all cases of danger.
5. Washing the baby with a wet cloth:
It is forbidden to soak a cloth into water in order to wash down the infant. Nevertheless one may ask a gentile to do so.
6. Is a Milah knife Muktzah on a Shabbos Bris?
The Milah knife is Muktzah and remains Muktzah even when there is a Bris on Shabbos.  It may therefore only be moved for the purpose of performing the Bris. After the Bris it remains forbidden to be moved for any purpose as is the law by all Muktzah objects. Nevertheless it is not required to immediately place down the knife after the Milah and rather it may be brought by the Mohel to a safe area for it to be kept until after Shabbos. It is forbidden to wash the blood off the knife even while the knife is still in the Mohel’s hand.
Is the foreskin Muktzah?
The foreskin is considered Muktzah. Nevertheless one may carry it to its destined place within the prepared earth.
7. May one perform his first Bris on Shabbos?
It is forbidden for one who has never circumcised before to perform a circumcision on Shabbos [even if he is the father of the child]. Similarly one who has never before performed Periah is forbidden to perform it on Shabbos.
It is permitted for the father to circumcise his son on Shabbos if he has done so once in the past.
8. Having two people do the Milah and Periah:
It is disputed whether one may have two people do the Milah and Periah, one person the Milah while the other the Periah, or if it all must be done by one person. [Practically the custom is to be lenient. Some rule that if the father of the child desires to do either the Milah or Periah and have another do the other part, then it is permitted according to all.]
 331/1 As the verse states “And on the eighth day circumcise his foreskin” The word “day” is expounded to include even Shabbos. [ibid]
 Such as the infant was ill and could not be circumcised on his eighth day. [ibid]
 331/4 The reason for this is because it is possible to circumcise the child after Shabbos without diminishing any fulfillment of the Mitzvah, as in any event it will not take place on its proper time whether it is done on Shabbos or after. [ibid] Meaning pushing it off one more day due to Shabbos does not lessen one’s quality of performance of the Mitzvah once it is past the 8th day. For this reason it must be delayed until after Shabbos.
 Between sunset and nightfall. [Siddur as rules Geonim and so is the custom of all Jewry today; This ruling is in contrast to the ruling of Admur in the Shulchan Aruch in 331/5 and 261/5. Practically according to Admur in the Siddur Bein Hashmashos only begins a few minutes [between 3 and 5 minutes-see Kitzur Hilchos Shabbos Miluim p. 99] after the visual sunset. The start of Nightfall varies in each area. An expert Rav is to be contacted in cases of any doubt as to the Halachic definition of the time the child was born.]
The ruling of Admur in the SHU”A 331/5: In the Shulchan Aruch Admur rules like the opinion of Rabbeinu Tam [unlike the Yereim/ Geonim] that Bein Hashmashos begins 15 minutes prior to nightfall, which in turn begins only 72/96 [depending on calculation of Mil in Admur] after sunset. Hence for up to 56.5-78 minutes after sunset it is still considered day for all purposes. Thus if a child was born during this time on Erev Shabbos he is to be circumcised the next Friday. If he was born at this time on Shabbos he is to be circumcised on Shabbos. The reason we are not stringent like the opinion of the Yireim in this case to suspect that perhaps it is already after Shabbos when he was born is because no one in these provinces are accustomed like the Yireim regarding Melacha on Erev Shabbos, hence there is no need at all to be stringent here and push off the circumcision due to their opinion. [ibid; No mention of the opinion of the Geonim is made by Admur in his Shulchan Aruch. Now although in 251/5 Admur rules regarding one who accepted Shabbos before Plag Hamincha of Rabbeinu Tam, to be stringent like Yireim, perhaps there it is different as by one accepting Shabbos at that time he has shown that he suspects for the opinion of the Yireim. Alternatively in that case there is nothing to lose by being stringent while here if one is stringent the Bris will be delayed from its proper time according to the main opinion.]
Other Poskim: The Shach [Yoreh Deah 266/11] brings the Maharahm Alshiker which rules to be stringent like the Geonim and push off the Bris if the child is born on Shabbos anytime between sunset and nightfall [of Rabbeinu Tam]. [This is unlike the ruling of Admur in the Siddur which rules completely like the Geonim that if born after nightfall of Geonim on Erev Shabbos, the Bris is to be done on Shabbos even though it is still Friday according to Rabbeinu Tam.] Birchei Yosef [brought in M”B 331/14] writes that the custom has spread like the Geonim in all Eretz Yisrael.
 As we do not override the Shabbos prohibitions if there is question as to whether the Mitzvah is to be performed that day. [ibid] As there is doubt as to whether Bein Hashmashos is part of the previous day or the coming day. Hence if born on Bein Hashmashos of Erev Shabbos the coming Shabbos is questionable whether it is the child’s 8th day or 9th day. In the case the child was born on Bein Hashmashos of Motzaei Shabbos it is questionable if the coming Shabbos is the 7th or 8th day.
 See Piskeiy Teshuvos 331/6 for a discussion in Poskim on the exact definition of the head coming out. Is it defined as having come out once it exists the Prozdor to the Beis Hachitzon, or is it only considered to have come out when it enters to the actual air of the world. The custom is like the latter opinion. [Chasam Sofer Yoreh Deah 167; Sidrei Taharah 194/26; Pischeiy Teshuvah 266/8]
 It is disputed in Poskim as to how one is to measure the majority of the head. Is it the majority of the forehead, or the entire forehead. [see Piskeiy Teshuvos 331/6]
 Regarding a child which was born breached [leg first] then when majority of the body exits it is considered to have been born. Practically once the naval has come out majority of the body is considered to have exited. [see Piskeiy Teshuvos 331/6]
 Such as a case that the mother had difficulty pushing the child out.
 See Piskeiy Teshuvos 331/6 in name of Migdal Oaz [Yaavetz]
 Pischeiy Teshuvah 266/8
 330/8; 331/3
 The Michaber Yoreh Deah 266/11 rules it is forbidden to circumcise an 8th month child which has not developed its hair and nails. This is brought as the first opinion in Admur in 330/8. The reason for this is because the child is Muktzah.
The Rama [ibid] however rules it is allowed to circumcise the child if there is doubt as to whether he was born in 7th or 8th month as perhaps he was born on the 7th and is considered a live child. However if it is certain the child was born the 8th month then even according to the Rama the child is not to be circumcised. Practically the custom is to circumcise even in such a case as we do not know for certain when she became pregnant with the child. Nevertheless Admur concludes as stated above that this is not to be done, even when it is a true doubt as to which month the child was born, as in a case of dispute it is better to act in a passive manner. [ibid]
 Minchas Yitzchak 4/123; Kinyan Torah 3/42; Chazon Ish Yoreh Deah 155 rule that today all premature babies, even in 8th month may have Shabbos desecrated on their behalf. Nevertheless since there are medical issues involved in circumcising a child prematurely, practically we do not circumcise any premature child. [Piskeiy Teshuvos 331/4]
 Piskeiy Teshuvos 331/4; see Igros Moshe Yoreh Deah 2/121 that if a child is in an incubator he is considered ill and cannot be circumcised until 7 days have passed after he is removed.
An Androgenus is a person born with the both the male and female genitals.
 As there is doubt in the status of his gender [ibid] and we do not overrule the Shabbos prohibitions in a case of doubt. [331/5]
 Which is defined as an unapparent foreskin, even if the foreskin is only undetectable when the child has an erection. [ibid]
 As although he is required to have blood dripped from his foreskin area, nevertheless since this is not a clear Biblical requirement it therefore does not overrule the Shabbos prohibitions. [ibid]
 As there is doubt as to whether an infant born through Caesarean is required to be circumcised immediately, or on his 8th day. The reason for this is because the Torah juxtaposes the command of circumcision on the 8th day to a woman’s impurity due to the birth, and since such a woman did not become impure due to the birth perhaps the obligation to circumcise on the 8th day does not apply. [ibid] [Background: The Gemara [Shabbos 135] suggests that a child born to a mother who did not become impure in the process is not required to be circumcised on the 8th day. Hence it does not override the Shabbos prohibitions.]
 As there is doubt as to whether an infant which was converted is required to be circumcised immediately upon the conversion, or on his 8th day. The reason for this is because the Torah juxtaposes the command of circumcision on the 8th day to a woman’s impurity due to the birth, and since such a woman did not become impure due to the birth perhaps the obligation to circumcise on the 8th day does not apply. [ibid]
 Two foreskins, one over the other.
 As there is doubt as to whether an infant which was born with two foreskins is required to be circumcised on his 8th day, as the Torah states “Circumcise his foreskin” which refers to a single foreskin. Therefore although such a child is to be circumcised on the 8th day due to doubt it nevertheless does not override the Shabbos prohibitions due to this mere doubt. [ibid]
 Known as a Mumar.
 Michaber Yoreh Deah 266/12
 Piskeiy Teshuvos 266/14
 The Bedek Habayis rules that nevertheless the child may be circumcised on Shabbos while the Shach [266/9] Taz [266/16] rule it is forbidden to circumcise the child on Shabbos
 Mahrsham 2/156; Sheivet Haleivi 4/132
 Pischeiy Teshuvah Yoreh Deah 266/14 rules he is to be circumcised on Shabbos. Mahrahm Shik [Even Haezer 20] and Beis Yitzchak [Even Haezer 29/11] rule the child may not be circumcised on Shabbos as some Poskim hold he has the status of a gentile and needs conversion, as well as that he is probably no better than the child of a Mumar/Mumeres.
 Yoreh Deah 266/13
 Yoreh Deah Shach 266/17
 Minchas Yitzchak 3/35; Igros Moshe Yoreh Deah 1/156
 A) It is a mere Grama b) This can lead others to push off doing their Bris on time. C) Perhaps a non-religious person will do the Bris improperly.
 Mahrshag 2/24; Sheivet Haleivi 4/132 and 135
 See Minchas Yitzchak 3/35
 Brought in Piskeiy Teshuvos 331/1
 Mahrsham 1/209; Beis Yitzchak 42; Beis Shearim 120; Minchas Yitzchak 2/75
 Avnei Neizer 2/392; Chayeh Adam 68/19 leaves this matter in question
 SSH”K 42 footnote 245
 Minchas Yitzchak ibid
 Piskeiy Teshuvos 331/5
 As rule Geonim
 Minchas Elazar 1/23; Divrei Yoel 18; Igros Moshe 4/62; Sheivet Haleivi 1/49; 4/132; Beir Moshe 2/61
 Har Tzevi Yoreh Deah 248
 Har Tzevi Yoreh Deah 248
 Rav SZ”A brought in Piskeiy Teshuvos 331/7
 As this is not the natural way of becoming impregnated and the verse states “a woman when she Tazria and has a son…” regarding Milah on the 8th day.
 As Periah is included within the Milah process. [ibid]
 It overrides the Shabbos prohibition [of causing wound] being that not doing so can lead to danger to the child. [ibid]
 This refers to a dressing or pad which has ointment smeared over it which is then placed on the wound
 Although applying a poultice was forbidden even in a case of illness that does not involve danger, here it is allowed as giving treatment to the area is considered to be a case of danger. [ibid]
 As the area that was circumcised can become lethally dangerous if not properly treated. [ibid]
 As one must even mix the oil and wine ointment together before Shabbos, even though doing so on Shabbos is a Rabbinical prohibition.
 For example, back in the day when they would place crushed cumin and wine mixed with oil on the area, then before Shabbos one would need to crush the cumin and mix the wine with oil. [ibid]
 Thus is they forgot to crush the cumin before Shabbos they would be allowed on Shabbos to chew it until it is crushed. Similarly if the wine/oil mixture was not prepared before Shabbos it would have to be placed separately, one after the other, onto the area in order to do it with an irregularity. However one would not be allowed to mix it on Shabbos. [ibid] As for the reason why it is allowed to do so with an irregularity even before the circumcision, seemingly this is because a child has a status of a Choleh Sheiyn Bo Sakana towards which all Rabbinical prohibitions may be done with an irregularity.
 Such as one is unable to chew the cumin and must thus grind it in its normal fashion. [ibid]
 331/7. It may not be implied from Admur 331/1 which only mentions this Halacha with regards to grinding the cumin and not regarding mixing the oil that he holds that Rabbinical prohibitions may be done, as it is always permitted to do a Rabbinical prohibition with a Shinui for the sake of one who is bedridden, and a child has the status of one who is bedridden. Vetzaruch Iyun as prior to the Milah, the child does not need this treatment, so how can it be allowed to enter the child into this situation. In any event Admur states explicitly in 331/7 that Rabbinical prohibitions may not be done if they could have been done before Shabbos.
 As Mila preparations that involve Shabbos transgressions do not override the Shabbos prohibitions being that they could be done before Shabbos, and it is only the Mila itself which overrides. Now although if the treatments are not given they could jeopardize the child’s life and hence indeed override Shabbos, nevertheless this is only after the fact. However initially it is forbidden to enter the child into this state of danger, hence allowing the treatment. Thus it is forbidden to go through with the circumcision. [ibid]
 Although Admur writes this case to be referring to one who did prepare the ointment before Shabbos and after the circumcision it spilled, nevertheless obviously it is not coming to exclude a case that one transgressed and did not prepare the ointment before Shabbos, as it is a matter of life and death for the child.
 The reason for this is because since these acts can be performed before Shabbos there is no need for them to override Shabbos. [ibid]
 A Chaluk is a cloth which has a hole pierced in its middle to be garbed onto the child’s Gid, which is then tightened around the Gid to prevent its skin from covering over the foreskin. Hence this hole may not be made on Shabbos. One may however tie a regular cloth around the Gid without making a hole. Likewise one may carry it with an irregularity through a Rabbinical forbidden domain such as by wrapping it on his finger. [ibid]
 Such as to carry the knife or the infant through a courtyard which did not have Eiruv Chatzeiros done. [ibid]
 As the Sages upheld their decrees even when a Kareis penalty will ensue due to abiding by it. [ibid]
 As the Sages did not decree against Shvus Deshvus in a case which involves a Mitzvah. [ibid]
 Such as sharpening the knife, or to carry it through a public domain. [ibid]
 A dispute of this matter is recorded in Admur. Some opinions rule it is forbidden to ever ask a gentile to perform a Biblical prohibition even in the case of a Mitzvah. Others however rule that even Biblical prohibitions may be performed through a gentile for the sake of a Mitzvah. Practically although one may not rely on this latter opinion regarding a typical Mitzvah, nevertheless regarding Mila since it itself overrides Shabbos one may rely on their words regarding the prohibited preparations. [ibid]
 As on the one hand the child can be circumcised at his home, and hence bringing the child to Shul involves no Mitzvah need for which the Sages allowed asking a gentile. This would apply even if the area is merely Rabbinically forbidden to carry in such as a courtyard without Eiruv Chatzeiros. Others however allow asking a gentile to bring the child to Shul [through a merely Rabbinically forbidden area of carrying] as circumcising in Shul will gather greater attendance which thereby beautifies G-d. [ibid]
 A Jew is not to carry the child from inside to outside or vice versa, even if another Jew will take the child from his hands before he puts the child down, as nevertheless a Rabbinical prohibition has been performed by this Jew, as he has performed Akirah or Hanacha. [ibid]
 Hence only minority of his limbs may be bathed in hot water, and only if the water was heated before Shabbos. [ibid see Volume 2 “The Laws of Bathing”]
 As all Melachas which occur unintentionally are permitted to be performed by a gentile even if they are inevitably done as a result of the action the gentile was asked to do. Thus although the Melacha of whitening is performed when soaking a cloth in water, one may nevertheless ask the gentile to enter the cloth into the water as the gentile is not being asked to whiten the cloth but rather to soak it. [ibid]
 It is defined as Muktzah Machmas Chisron Kis
 This follows the ruling of the Taz/Magen Avraham in 331 that even on a Shabbos Bris the knife is Muktzah. However the Rama and Shach Yoreh Deah 266/2 rule that the knife is not Muktzah at all as something cannot be Muktzah for only part of Shabbos.
The M”B 310/15 rules that in a time of need, such as there is suspicion of robbery, one may rely on this lenient opinion to hide the knife even after one already placed it down. The Sheivet Haleivi [4/135] rules likewise saying that majority of Poskim are lenient.
 As one may only wash vessels on Shabbos if they have a Shabbos use. [323/6]
 Yoreh Deah Pischeiy Teshuvah 266/2
 As he may come to perform it incorrectly and hence end up desecrating Shabbos for no need. [ibid]
 So is implied from Admur. However there are Poskim which allow a father to do so even for the first time. [See Piskeiy Teshuvos 331/9]
 We do not claim that if another Mohel is available the father should not do so, due to that he is fixing his child which is Tikkun Keli [ibid] as in truth every Mohel is fixing the child and not just the father. [M”B 331/39]
 The Michaber [Yoreh Deah 266/14] rules it is forbidden to have two different people perform the Milah. The Rama however rules that doing so is permitted, although initially one is to be stringent. Many Poskim however argue on this conclusion, ruling that even initially one may have two different people perform the Milah/Periah, and so was the widespread custom in Poland. [M”B 331/36]
 M”B ibid
 Eretz Tzevi 63
 As the Mohel is the emissary of the father and it is hence as if only one person is doing the Milah/Periah. [ibid]