We are continuing in siman 1, discussing a child born on the 30th of Cheshvan or Kislev, and how to calculate his bar mitzvah in a year which is missing those days.
It is important to clarify that when the Gemara refers to a two-day Rosh Chodesh, the first day of Rosh Chodesh is also the 30th and final day of the previous month. Only the next is actual beginning of the month, Rosh Chodesh (lit. head of the month)–the second day of the two-day Rosh Chodesh, which is the first day of the new month. But on the other hand , the first day (day 30) is also called Rosh Chodesh. This point is relevant in shtaros (documents), where, if the document is written on the first day of a two-day Rosh Chodesh, the document is dated as “the first day of Rosh Chodesh, which is the last day of [x] month”.
Thus, the Chayei Adam considers the possibility that if a child is born on the 30th of Cheshvan or Kislev, although these days are considered the first day of Rosh Chodesh, since they are actually the final day of the previous month, maybe the bar mitzvah should be calculated to the final day of the previous month as well (i.e., 29th of Cheshvan or Kislev). Nevertheless, the bar mitzvah is calculated to the first day of the next month (Kislev or Teves, the “true” Rosh Chodesh), because the date of birth is considered connected to Rosh Chodesh rather than to the previous month. So primarily, we look at it as Rosh Chodesh (as in the shtar, that it is called Rosh Chodesh first).
There is one more Adar scenario which the Chayei Adam does not discuss. Adar is a month which generally has 29 days. However, when an Adar is added, the first Adar has 30 days, and the second Adar has 29. When a child who is born in a leap year on the 30th of the first Adar, and becomes bar mitzvah in a regular year, one would have assumed that his bar mitzvah would be on the first of Nissan, as we have learned regarding Cheshvan and Kislev. However, regarding Cheshvan and Kislev, the 30th of those months is part of the Rosh Chodesh of the coming month. The 30th of the first Adar is part of the Rosh Chodesh of the second Adar, but has no connection to Rosh Chodesh Nissan. Thus, the argument can be made that since the 30th of the first Adar and the Rosh Chodesh of Nissan have no connection, such a bar mitzvah should be calculated differently.
The Shulchan Aruch does not discuss this case. The Aruch Laner raises the question, and suggests that the bar mitzvah must be tied to Adar in some way, so the bar mitzvah should be calculated to the last day of Adar. Other poskim maintain that he should not be considered a bar mitzvah until Rosh Chodesh Nissan.
A final case regarding Cheshvan and Kislev is if a person is born on the first of Kislev or Teves in a year where there were only 29 days in Cheshvan or Kislev, and in the year of their bar mitzvah Cheshvan or Kislev have 30 days. When the boy reaches the 29th day of the previous month, they will have completed 13 full years of life, even if it is not yet the first of the new month. Thus, in such a case, their bar mitzvah is calculated to the 30th of the previous month (i.e., the first day of Rosh Chodesh), rather than the first day of the next month (the second day of Rosh Chodesh). However, some poskim do not count him for a minyan until the first on the next month. A person should ask their rav.
Summary
- If a child is born on the 30th of Cheshvan or Kislev, and in the year of their bar mitzvah the date does not exist, their bar mitzvah is calculated to the first day of the next month.
- If a child is born on the 30th of the first Adar, and the year of his bar mitzvah is a regular year, some suggest that his bar mitzvah should be on the 29th of Adar, and some suggest it should be on the first of Nissan.
- If a child is born of the first of Kislev or Teves in a year where there was only 29 days in the previous month, and in the year of their bar mitzvah there were 30 days in the previous month, their bar mitzvah is calculated to the 30th of the previous month rather than the first of the next month. A shaalah should be asked.
