The first of the Torah's 613 Misvot is Periya Ve'riba – the obligation to procreate. The source for this Misva is G-d's command to Adam and Hava right when they were first created, "Peru U'rbu" – "be fruitful and multiply" (Bereshit 1:28).

The Sefer Ha'hinuch writes about this command, "Ve'hi Misva Gedola" – this is an especially important Misva, because it in a sense encompasses all Misvot in the Torah, as the children one produces will, please G-d, fulfill all the Misvot. The Misvot are intended not for angels, but rather for human beings, and so by reproducing, we ensure the continued observance of the Torah. Implicit in the Sefer Ha'hinuch's discussion is the assumption that this Misva requires not merely producing children, but also educating them to become Torah-observant adults.

The Sefer Ha'hinuch adds that this Misva applies at all times and in all locations. The obligation is incumbent upon only men; women do not bear an obligation to produce children. The Sefer Ha'hinuch warns that those who neglect this Misva are liable to severe punishment.

An interesting question arises as to whether one fulfills this Misva if he begets a Mamzer (illegitimate child). This can happen in two different situations – when a Ger (Halachic convert) marries a Mamzeret, a permissible union, the products of which are Mamzerim; and when one engages in relations with somebody with whom relations are forbidden and carry the punishment of Karet (eternal excision from the Jewish Nation). This includes situations such as incest and adultery. Interestingly enough, the Talmud Yerushalmi indicates that even in the latter case, where a person begot a child through a strictly forbidden relationship, he fulfills the Misva of Periya Be'ribya. The Bet Yosef (commentary to the Tur by Maran, Rav Yosef Karo, author of the Shulhan Aruch) cites this position in the name of the Ritba (Rav Yom Tob of Seville, Spain, c. 1260-c. 1320).

At first glance, we might wonder how this position can be reconciled with the famous principle of "Misva Ha'ba'a Ba'abera," which disqualifies a Misva performed via a transgression. How can one be considered to have fulfilled a Misva by performing an act which constitutes a violation of one of the most severe Torah prohibitions?

The Minhat Hinuch (Rav Yosef Babad, 1801-1874) answers that the rule of "Misva Ha'ba'a Ba'abera" applies only when the performance of a Misva and the violation of a sin occur simultaneously. The classic case is when a person picks up somebody else's Etrog to steal it, intending at the same time to fulfill the Misva of the four species on Sukkot. The thief does not fulfill the Misva, because the Misva act was also an act of sin. If, however, a Misva was facilitated through a forbidden act which preceded it, the Misva has nevertheless been fulfilled. In the case of Periya Ve'ribya, the Minhat Hinuch explains, the Misva is fulfilled not through the act of intercourse, but rather when the child is born. The relationship facilitates the Misva, but is not the Misva act itself. Therefore, one who has an incestuous or adulterous relationship which produces a Mamzer nevertheless fulfills the Misva of procreation, since the forbidden act which facilitated the Misva occurred before the fulfillment of the Misva.

This principle also affects a different question – when one should have in mind to fulfill the Misva of Periya Ve'ribya. Halacha follows the view that "Misvot Serichot Kavana" – one must have in mind to fulfill the Misva when the Misva act is performed. According to the theory advanced by the Minhat Hinuch, one does not need to have in mind to fulfill the Misva of Periya Ve'ribya during marital relations, because the Misva is fulfilled not at that time, but rather later, when the child is born. Hence, when one's child is born (specifically, the first boy and first girl, as the accepted view is that one fulfills the Misva by begetting one son and one daughter), he should have in mind at that time that he fulfills the Misva of Periya Ve'ribya.

However, the Shulhan Aruch writes (Eben Ha'ezer 1), "One is obligated to marry a woman in order to procreate." This formulation suggests that the Misva of Periya Ve'ribya is fulfilled at the time when one marries, as this is the way one procreates. For this reason, when the Minhat Hinuch served as Mesader Kiddushin, officiating at a wedding, he would instruct the groom under the Hupa to have in mind that he fulfills the Misva of Periya Ve'ribya, in order to satisfy the view implied by the Shulhan Aruch.

More lectures from Rabbi Eli Mansour

Parashat Ekeb: G-d’s Eternal Love for His Nation

Misva #1: Periya Ve’riba – Procreation

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If One Damages Somebody’s Property In His Sleep, Under Intoxication, While Celebrating, or During a Sports Game