According to the understanding of many commentators "pru u'revu" (be fruitful and multiply) is a positive commandment which is not fulfilled unless a man has both a son and daughter as offspring. Based on this understanding it would seem that Yitzchak did not fulfill this commandment. Is this correct? Are there any sources that indicate that either:

  • He had a daughter
  • He was exempt from this mitzvah
  • 2
    Can't we ask the same of Avraham, Yehuda, Yosef, Moshe, and Aharon (among others that have no explicit daughters but have explicit sons in Tanach)?
    – Double AA
    Nov 13, 2012 at 16:56
  • In fact, of all of Yaakov's twelve sons I think only two are known to have had any daughters (Yocheved to Levi, and Serach to Asher) but we have multiple lists of all their sons.
    – Double AA
    Nov 13, 2012 at 17:02
  • 1
    chazal say that avraham had a daughter. as far as the rest, you can certainly ask; I thought yitzchak was more interesting specifically because of the chazal about Avraham having a daughter (an it's topical) rchaimqoton.blogspot.com/2006/11/daughter-of-abraham.html
    – user1668
    Nov 13, 2012 at 17:10
  • 1
    Of what import is it whether one of the Avoth fulfilled the technical requirements of a Mitzvah that is beyond his control?
    – Seth J
    Nov 13, 2012 at 18:29
  • 1
    noachide-laws? Since when is Pru uRvu one of those? || @SethJ We don't know that it was beyond his control; perhaps he should have found a new wife. And I don't see what "technical requirements" have to do with anything. As to why we should inquire if the Avot kept mitzvot deoraita, see judaism.stackexchange.com/q/4078 and the various opinions thereof.
    – Double AA
    Nov 13, 2012 at 18:33

2 Answers 2


Per Igros Moshe Even HoEzer2 18 the Mitzva of Peru U'revu is Tashmish - since it is not in a persons control whether a child will be born. There is a Chiyuv of Tashmish in regard to Peru U'revu so long as a person does not have a boy and a girl. Based on this Yitzchok was Mekayem the Mitzva of Peru U'Revu with Tashmish, and as to not having a girl that was beyond his control.

  • "Yitzchok was Mekayem the Mitzva of Peru U'Revu with Tashmish": source? or is this an assumption?
    – msh210
    Nov 13, 2012 at 18:20
  • 1
    Doesn't the question specifically ask according to the other more standard understandings?
    – Double AA
    Nov 13, 2012 at 18:21
  • 1
    I"M is not the non-standard explanation. It is very standard. You can't have an obligation to do something that is not within your control. The mitzvah is the act that brings about the resulting peiros. That act is also the fulfillment of the mitzvah of Ona. Once one has had a boy and a girl, the obligation to do that act has been mitigated to a degree by the fact that one goal of that act has been accomplished.
    – Yahu
    Nov 14, 2012 at 6:09
  • 3
    @Yahu Good to see you around! I'm not sure, though, why you can't have an obligation to do something that isn't within your control. We generally call such a person Oneis and exempt him from the obligation.
    – Double AA
    Nov 14, 2012 at 7:01
  • 1
    @DoubleAA , You proved the point exactly: The Torah would not give an obligation to someone to do something not within his control to accomplish: Oneis Rachmana Patrei. Patrei=no obligation.
    – Yahu
    Jan 22, 2014 at 5:14

Gemarah (Taanis 11a) states a person cannot be intimate with his spouse during an "eis tzorah" like drought, unless he "lacks children". The Gemara learns this out from Yosef who had his kids "before" the famine (Bereishis 41:50). Rashi there explains this to mean that he fulfilled the mitzva of p'ru u'rivu. There is no indication that Yosef fathered a girl. Thus there is a precedent for a different interpretation of the obligation of p'ru u'rivu before matan torah. So we can assume this would extend to Yitzchak as well.

  • 1
    Maybe yosef had a daughter? You don't have precedent until you establish that to be not true.
    – Double AA
    Nov 14, 2012 at 21:33
  • A reverse precedent?
    – Seth J
    Nov 14, 2012 at 21:42
  • 1
    @DoubleAA maybe yitzchak had a daughter? The op seems to be assuming that lack of a positive mention of such is proof enough Nov 15, 2012 at 1:07
  • @SethJ the precedent is valid because it is before matan torah, which is the only event that may have changed the definition of pru u'revu Nov 15, 2012 at 1:08
  • I'm pretty sure the OP does think that the lack of a positive mention of a daughter is proof enough because he asks if anyone has any evidence of one.
    – Double AA
    Nov 15, 2012 at 1:14

You must log in to answer this question.