The first commandment in the Torah is Peru U'Revu, the commandment to "be fruitful and multiply" (Bereshit 1:28).

When does the obligation to fulfill this commandment begin? Does the Mitzva of Peru U'Revu start at 13, when a child becomes Bar Mitzvah, and is obligated in Mitzvot? Or perhaps 18, since the Mishnah tells us that 18 is the age to get married? Or perhaps another age?

If not 13 - why not? (sources please)


3 Answers 3


From Pirkei Avos 5:22, 18 is the recommended beginning age for getting married (and hence reproducing).

The conditions for having fullfilled the mitzvah of Peru U'Revu (Yevamos 61b) don't mention anything about the age of having done so, only the number of children he has had.

So if a man has had children at any age even before the age of 13 (see Sanhedrin 76b) then he has fulfilled the mitzvah. However, he isn't obligated to do so before the age of 18. If he hasn't gotten married by age 20 then he is guilty of not having done the mitzvah.

  • 2
    Do you have an halachic source for "he isn't obligated to do so before the age of 18"? For "If he hasn't... by age 20 then he is guilty"?
    – msh210
    Commented Oct 23, 2011 at 4:20
  • I didn't find it at 5:22, do you know of an alternate numbering? Also, I wouldn't necessarily consider Avos a halachic source.
    – yitznewton
    Commented Oct 23, 2011 at 16:58
  • 2
    @yitznewton This paragraph is a later addition to the Mishna so some versions have it and some don't (a fact also which makes it an even weaker halachik source).
    – Double AA
    Commented May 12, 2013 at 20:58
  • Related: judaism.stackexchange.com/q/16395
    – Fred
    Commented Jun 27, 2014 at 20:10

The Torah Temima in Breishis 1:28 #65 says that the Rambam in Ishus Perek 15 Halacha 2 says that the Mitzva begins at 20. Although it says to get married at 18, until 20 you are not disregarding the Mitzva. The Torah Temima also mentions that Peru U'Revu is connected to the same age as those that go to war, which is at 20.

  • 2
    That is a very interesting analysis of the Rambam, since he patently states that the Mitzvah is in effect from a younger age (cf. Mbrevda's answer: judaism.stackexchange.com/a/13233/5) but that one isn't in violation of Halachah until age 20.
    – Seth J
    Commented Jan 11, 2012 at 16:23

According to the Rambam from the age of 16 or 17, however one isn't in violation of the commandment unless he is still unmarried at the age of 20.

  • 1
    Your link needs mending. See also Gershon Gold's answer.
    – msh210
    Commented Jan 11, 2012 at 15:40
  • @msh210 - I inserted a new link for Mbrevda. Also, the Rambam does say what Mbrevda says it does; the Torah Temimah in Gershon's answer seems to be interpreting Rambam's statement about a person not violating Halachah until age 20 to mean that the Mitzvah doesn't come into force until then, even though Rambam clearly states that 16 or 17 is the age to fulfill the Mitzvah.
    – Seth J
    Commented Jan 11, 2012 at 16:22
  • 1
    @SethJ, I agree that that's what the Rambam says. But I had no way of knowing that until the link was right. :-)
    – msh210
    Commented Jan 11, 2012 at 19:23

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