Bar Mitzvah boys Leining-Having the Bar Mitzvah boy Lein from the Torah:
Introduction: It is an old custom for the Bar Mitzvah boy to receive an Aliyah to the Torah on the occasion of his Bar Mitzvah, in order to publicize that he has now reached the age of Mitzvos. In previous times when it was customary for the Olah to also be the Baal Korei, every Bar Mitzvah boy would not just receive the Aliyah but would also read the portion from the Torah. Accordingly, children of Bar Mitzvah age would need to be taught how to read from the Torah properly. However, over the generations the custom evolved to having a set Baal Korei read from the Torah, independently of the person receiving the Aliyah. Accordingly, it became no longer necessary for children of Bar Mitzvah age to be taught to read from the Torah. Nonetheless, as will be explained next, some communities continued not only with the custom of educating the child to read his Aliyah, but furthermore to have him read the entire Parsha of that week.
The custom: Many communities of Ashkenaz are accustomed to have the Bar Mitzvah boy read from the Torah on the Shabbos of his Bar Mitzvah [if it falls on Shabbos, or the Shabbos after his Bar Mitzvah]. This custom is mentioned in the Poskim, although it is unclear if the custom mentioned in these Poskim refer to him to simply reading his Aliyah, or to him reading the entire Parsha. [The reason behind the custom of having him read at least his Aliyah even though we now have a set Baal Korei, is due to the fact that in previous times children would receive certain Aliyos, such as Maftir, and hence in order to publicize that he is now Bar Mitzvah, he would read from the Torah in addition to simply getting an Aliyah. However, today that we no longer are accustomed to call up children for an Aliyah, the Aliyah itself serves as this publication and there is hence no need for him to also read from the Torah.] Practically, today the custom of Ashkenazi and Lithuanian communities is for him to read the entire Parsha. This is not the custom of Chassidim.
The Rebbe’s opinion-Negation of the custom: Practically, the Rebbe was opposed to the above custom of the child reading his Parsha on the Shabbos after his Bar Mitzvah, stating that it has no real source, and takes time away from investing into the real preparations that the child is required to do, such as learning and becoming an expert in the practical laws that will become relevant to him after his Bar Mitzvah. However great the Mitzvah of reading from the Torah is, learning Torah assiduously is even greater. [The reading of the Parsha for a Bar Mitzvah boy takes much preparation time, usually beginning a year prior to the Bar Mitzvah, with weekly lessons in reading the Parsha. In some communities this has become accepted almost like an obligation, and the peer pressure and accepted practice forces the child to do so. Nonetheless, in truth there is no obligation for the Bar Mitzvah boy to read his Parsha on the Shabbos after his Bar Mitzvah, and doing so places extra and unnecessary pressure on the child. The child must be educated to focus on the most important aspects of learning prior to his Bar Mitzvah and not matters that are mere superfluous. However, if the child is already being properly educated in his required learning, and if he is duly adapted towards Torah reading, then he may be educated in this as well as a secondary education.]
It is an old custom of Jewry for the Bar Mitzvah boy to read from the Torah by the Parsha of his Bar Mitzvah. Nonetheless, it is not necessary for him to read the entire Parsha, and this is a fairly recent custom. Practically, the widespread custom today amongst much of Lithuanian Jewry is for the Bar Mitzvah boy to read his entire Parsha from the Torah, while the custom amongst Chassidim is not to have him read anything at all, not even his Aliyah. The Rebbe indeed discouraged the former custom saying it takes away time from being invested into the more necessary preparations of Torah learning.
 See Nitei Gavriel Bar Mitzvah 13; Shaareiy Bar Mitzvah [Heiachal Menachem] p. 4
 See M”A 282 in end; Biur Halacha 136:1 “Beshabbos Veyom Tov”; See Piskeiy Teshuvos 136:7
 See M”A 225:4 regarding him reading from the Torah in public, that this would publicize the fact that he is Bar Mitzvah [indeed in previous times when it was customary to call children to the Torah, especially for Maftir, only thefact that he read from the Torah publicized the fact that he ius of Bar Mitzvah age, however, see Shaar Hatziyon 225:7 that today that we no longer call up children to the Torah, the calling up itself serves as a sign that he is Bar Mitzvah]; Levushei Mordechai Kama 37; Shaar Hatziyon 225:7
 See Michaber 141:2; Tzemach Tzedek 35:4
 See M”A 225:4
 Beis Yosef 141; Tur 141 in name of Rosh; M”B 141:8; Kaf Hachaim 141:15; See Tzemach Tzedek 35:4 that this custom of having a set Baal Korei was innovated in the times of Tosafos. However, during that time, the main custom was simply for the Baal Korei to assist the Olah in his own reading, and thus the Olah would still be the one reading out loud, and the Baal Korei would whisper silently to him. [See Tosafos Bava Basra 15a and Menachos 30a] However, later on the custom became to do the opposite for the Baal Korei to read aloud and for the Olah to read silently. [See Rosh Shabbos 1]
 See Minhagei Wormz 289; Leket Hakemach Hachadash 141:5; Keser Shem Tov [Gagin] p. 15 that so is the custom in London; Nitei Gavriel ibid
 M”A 225:4 “When the child reads the first Shabbos which would publicize to all that he is Bar Mitzvah”; Maharil Hilchos Kerias Hatorah p. 63 “When his son became Bar Mitzvah and read from the Torah”; Yosef Ometz p. 357 “On the Shabbos he becomes Bar Mitzvah he becomes old enough to read from the Torah..the Rabbis instituted for him to read from the Torah on the first Shabbos.; Poskim in Nitei Gavriel ibid footnote 1
 See Igros Kodesh 20:118 that “the custom was never to do so” which seemingly refers to the reading of the entire Parsha, as the reading of the child’s Aliyah was certainly practiced in the past, as explained in the introduction and Poskim ibid. Nonetheless, it is clear that the Rebbe understands that even the above Poskim only refer to one’s reading of his Aliyah and not of the entire Parsha
 Admur 282:5; 53:13 “A Katan may receive an Aliyah”; Michaber 282:3; Rambam Tefilla 12:17; Megillah 23a “Everyone counts for the seven Aliyos including a child” and Mishneh 24a “A child may read from the Torah and translate”; Yerushalmi Brachos 7b; See Hagahos Maimanis Tefilla 12:17 that if there are no Yisraeilim in the Minyan then one is to call up a child or woman
 M”A 225:4; See the following Poskim that a child is an invalid Baal Korei until Bar Mitzvah: Admur 282:5; M”A 282:6; Mishpat Tzedek 3:43; M”B 282:13; See in great length article of Rav Avraham Yitzchak of Mir, printed in Yagdil Torah N.Y. ibid, that the vast majority of Poskim, Rishonim and Achronim rule this wat including the Bahag, Rambam, Rash, Baal Hamaor, Milchamos, Semag, Rosh, Tur; See Tzemach Tzedek [Rav Meir Milameid] O.C. 35; Chidushim Megillah 3:6-3; Kneses Hagedola 282; Olas Tamid 282:3; Tosefes Shabbos 282:7; Kaf Hachaim 282:23; So rule regarding Megillah that a child is invalid: Michaber 689:2 based on Tana Kama in Megillah 19b and so rules: Rosh; Bahag; Levush; Bach; Olas Shabbos 689:3; Peri Chadash; According to this approach the Mishneh in Megillah 24a which states “A child may read from the Torah and translate” is interpreted to refer to a child getting an Aliyah and not to him reading from the Torah on behalf of the public.
 See the following Poskim that it is no longer the custom to give children an Aliyah until their Bar Mitzvah: Admur 282:7; M”A 282:6; Elya Raba 282:6; Tosefes Shabbos 282:7; Mateh Yehuda 282:6; M”B 282:12; Kaf Hachaim 282:24; See Radbaz 1:566 as explains Levush Serud on M”A ibid versus Machatzis Hashekel ibid if a child may be called up for Kohen
 Shaar Hatziyon 225:7
 Nitei Gavriel ibid
 Igros Kodesh 18:222; 20:118; 137
 See Igros Kodesh 18:222 that this custom was started fairly recently; 20:118 that this custom was never followed in the past; See previous footnotes that the seeming intent of this statement is that it was not customary for him to read his entire Parsha even in previous times
 Igros Kodesh 18:222 [In this letter, the Rebbe bemoans to the writer the fact that his son had read the entire Parsha, as customary, and do not invest his time for the more necessary preparations such as the adding of learning Torah.]
 Igros Kodesh 18:222