Using another persons Daled Minim:
A. First day of Sukkos:
On the 1st day of Sukkos [in Eretz Yisrael and the first two days of Sukkos in the Diaspora as will be explained next] one only fulfills his obligation with a set of Daled Minim which he personally owns. Therefore when using someone else’s Lulav one must receive it as a present on condition to return. Thus the giver should explicitly say to the recipient “It is a present on condition you return it”. If this was not explicitly said and rather the Daled Minim were simply given to the person without mentioning anything, he has nevertheless fulfilled his obligation. If however the receiver did not know the law that he must own the Daled Minim then he has not fulfilled his obligation and is to be given it again as a present on condition to return.
B. Second day of Sukkos in Diaspora:
On the second day of Sukkos in the Diaspora one may not say a blessing over a Lulav that he does not own. Hence he is to be given the Lulav as a present on condition to return.
C. Giving it to a Katan:
On the first day of Sukkos in Eretz Yisrael, and the first two days of Sukkos in the Diaspora, one is not to give his personal Daled Minim to any child below the age of 13 for a boy and 12 for a girl, to fulfill the Mitzvah. Thus one must purchase a separate set of Daled Minim for the children to shake. Alternatively, on the first day in Eretz Yisrael, and on the second day in the Diaspora, one may give the child his personal Daled Minim if all the adults have already fulfilled the Mitzvah. However on the first day in the Diaspora one is not to give children his personal Daled Minim even after all the adults have already fulfilled the Mitzvah, as one must use his own set of Lulav also the next day.
If the child does not have his own set: If one does not have another Lulav available to give the children then he may give the children his personal Lulav as a borrowed item, and not as a present. Thus he is not to say “a present on condition to return”, as he does when giving it to adults. Nevertheless some Poskim rule that the child may not say a blessing on this shaking.
If one gave the child the set as a present: If one did give the child the Daled Minim as a present then no other adults may fulfill their obligation with this Lulav until the start of Chol Hamoed. If one gave the child his Daled Minim without mentioning anything at all, and he also did not have anything in mind, then it is considered lent to the child and other adults may still fulfill their obligation with it even on the first days of Sukkos by having it given to them as a present.
D. Returning the Daled Minim:
If the receiver did not return the Daled Minim: If the receiver did not return the Daled Minim he has not fulfilled his obligation. This applies even if he was given the Daled Minim without having it said explicitly that it was a present on condition to return.
Returning the Daled Minim to the owner: The receiver is to return the Daled Minim to the owner as a present with intent that the owner acquires it [as opposed to lending the Daled Minim to the original owner].
May the receiver give the Daled Minim to another to fulfill his obligation? The receiver may give the Lulav and Esrog to another person as a present on condition to fulfill his obligation and this person himself may also give it to another, as long as the original owner receives it in return, as originally stipulated.
E. Chol Hamoed:
During Chol Hamoed one does not need to use a Lulav which he owns. One may use another person’s Lulav without permission, assuming he doesn’t mind. However it is forbidden to remove the Lulav from its place unless the owner was asked. [Nevertheless it is proper to give another person one’s Lulav as a Matana Al Menas Lehachzir also during Chol Hamoed, and this is beneficial for both the giver and the receiver. So was the custom of the Rebbe.]
F. A stolen Lulav set:
One who buys a stolen species only fulfills his obligation if the owner has given up hope in retrieving it.
Must one give his wife the Lulav and Esrog on condition of returning?
May a child give another child his Lulav and Esrog to shake?
Yes, if the child is above age 6.
Must one shake his own personal set of Daled Minim if he is shaking in the old city of Jerusalem?
According to some Poskim one is to use Daled Minim that he owns or receive it as a “Matana Al Menas Lehachzir” throughout all seven days of Sukkos.
May one buy Daled Minim from a child?
One may not buy any of the Daled Minim from a child under Bar Mitzvah unless the child does not own the Daled Minim and is selling them on behalf of another person. If one already shook Daled Minim that was purchased from a Katan then on the first day(s) one is to shake again without a blessing.
May one give married women Daled Minim to shake on the first day(s) of Sukkos?
Some Poskim rule that one may not give a married woman Daled Minim to shake on the first day(s) of Sukkos unless he explicitly states that it is a Matana Al Menas Lehachzir, and the husband has no portion in it, and he is giving it to her specifically to fulfill the Mitzvah.
 M”B 649/15; Hayom Yom 15th of Tishreiy; Peri Megadim A”A 649/9; Bechureiy Yaakov 649/15
The reason: The reason for explicitly saying “Matana Al Menas Lehachzir”, even though it is valid also without saying it, is because the Peri Megadim A”A 649/9 brings a dispute whether one fulfils his obligation if it was not explicitly said and hence suggests that one is to initially mention it. See also Choshen Mishpat 241/5 for an opinion that rules a present given as “Stam” is only valid if one did not have in mind to condition the present on anything. However it requires further analysis if this is the reason behind our custom mentioned in Hayom Yom as Admur 14/6 rules that whenever one gives a Tallis Gadol to someone to wear for the Mitzvah he may say a blessing as it is considered a Matana Al Menas Lehachzir. Hence Admur does not suspect at all for a dissenting opinion brought in the Peri Megadim. Perhaps then the explanation is based on a spiritual reason as mentioned in Hayom Yom “that it benefits the giver and receiver”. The Bikureiy Yaakov ibid however mentions that if the receiver did not know the law that a borrowed set is invalid, then if it was given without mentioning “it is a present” he has not fulfilled his obligation as he certainly has not had in mind to acquire it.
As for why we do not say “on condition to return to me”: Seemingly this is in order to lessen the condition of ownership upon the receiver, as explained in Choshen Mishpat 241/6-7; Sdei Chemed Asifas Dinim “Daled Minim” 3/19; Biur Halacha 658 “Bestama”; that when “me” is omitted one fulfills his obligation even if he returns it after the festival, or even if he returns money instead. [The above sources are mentioned by the Rebbe in quote of the mentioned custom in Hayom Yom. The Sdei Chemed there explains that saying “me” is less beneficial for the receiver then omitting “me”. However giving the Daled Minim Bestam, without mentioning anything, he writes is an even higher level, as one fulfills the Mitzvah right away and not retroactively as is the case when one says “on condition”.
 658/5; Admur 14/6 regarding Tzitzis
As since he gave him the Daled Minim in order to fulfill his obligation, certainly he has given it to him with intent to acquire as a present. [ibid]
However see Choshen Mishpat 241/5 for an opinion that rules a present given as “Stam” is only valid if one did not have in mind to condition the present on anything.
 Bikureiy Yaakov 649/15 [brought in M”B 649/15] mentions that if the receiver did not know the law that a borrowed set is invalid, then if it was given without mentioning “it is a present” he has not fulfilled his obligation as he certainly has not had in mind to acquire it. Vetzaruch Iyun what to do by Mivtzaim as the receiver does not really even understand that he is to acquire it, even when one says it is a present on condition to return.
 Michaber ibid
The reason: As a child is unable to return a present.
 M”A 658/8; P”M 658 A”A 8; Bikurei Yaakov 658/18; Chayeh Adam 152/11; Igros Moshe 3/95 See Ketzos Hachoshen 241/4; Chanoch Lanaar 25
 Michaber ibid
 M”B 658/23; Biur Halacha 649 “Pesulei”
 Opinions brought in M”B 658/28; Ashel Avraham Butchach Tinyana
The reason: As one fulfills the Mitzvah of Chinuch even if the child does not fulfill the Biblical Miztvah.
Other opinions: Some Poskim rule one does not fulfill any Chhinuch obligation if the child does not own the set of Lulav. [M”A 658/8; P”M 658 A”A 8; Bikurei Yaakov 658/18; Chayeh Adam 152/11]
 Chayeh Adam 152/11
 Michaber ibid; Biur Halacha “Eino Muchzar”
 Chochmas Shlomo 658
 Michaber 658/5; see also Admur 14/6
 The reason: As we assume one desires to have the item returned and is not giving it to them for keeps. [M”B 658/18]
 Michaber 658/5; see also Admur 14/6
 Michaber 658/5
Other Opinions: There are Poskim which are stringent to not allow the receiver to give the Daled Minim to another unless he received explicit permission. [See M”B 658/21; Biur Halacha Umihu]
 Hayom Yom 15th Tishreiy. So is implied from the words “especially on the first day”. Perhaps however it is only coming to include the second day in the Diaspora and not Chol Hamoed.
 Bikureiy Yaakov 657/5
 Aruch Hashulchan 657/3
 See Hiskashrus
 See Piskeiy Teshuvos 658/11; Minchas Yitzchak 5/65; Kaf Hachaim 658/66
 Ksav Sofer 129 brought in Biur Halacha 658 “Lo Yitnenu”; Minchas Yitzchak 5/65
 Piskeiy Teshuvos ibid
 Bikureiy Yaakov 654/5 brought in Kaf Hachaim ??; Piskeiy Teshuvos 564/3