Another mitzva, the mitzva of procreation (pru u-revu) is fulfilled by means of the mitzva of ona. This, too, demonstrates the greatness of the mitzva of ona, as through it a man and woman become privileged to partner with God in creating a new human being. Nevertheless, the mitzva of ona is not dependent upon the mitzva of pru u-revu. Ona applies even when there is no chance that the sexual union will lead to pregnancy, such as when the woman is already pregnant or nursing, has reached menopause, or is infertile.
The Sages say that the greater the joy accompanying the mitzva of ona, the finer the character of the future children (Eruvin 100b; below, 2:5). In contrast, if the couple’s sexual union lacks devotion and love, imperfections may manifest in the resulting children (Nedarim 20b, explained below in 2:13).
Similarly, R. Yitzḥak Aboab writes: “When husband and wife love each other, have intercourse when at peace with each other, and have intent to produce worthy offspring, God grants their wish and gives them worthy children” (Menorat Ha-ma’or, ner 3, klal 6, ḥelek 2).
The sages of the Jewish mystical tradition said that every act of marital sexual union undertaken in sanctity and love infuses the world with more life and blessing. R. Yeshayahu Horowitz writes in his classic Shnei Luḥot Ha-brit (Shlah, Sha’ar Ha-otiyot, Kedushat Ha-zivug §402):
Each and every act of intercourse, when undertaken in sanctity, will have a positive impact. Even if the wife does not conceive…[the husband] is not wasting seed; rather, a holy soul comes into existence as a result…. For a soul comes into being with every act of intercourse, and the offspring of others are then endowed with these souls…. This is why Avraham could sleep with Sarah even though she was barren. It was not, God forbid, a waste.
Zohar explains that the perfect love and devotion that infused the intimate relations of these two righteous people, Avraham and Sarah, led to the creation of souls in the supernal realms, which then descended to this world, and with which children of various families were endowed. When those children grew up, they were drawn to Avraham and Sarah, who converted them to faith in God. These are the souls referred to in the verse (Bereishit 12:5): “The souls they created in Ḥaran” (Zohar III 168a).
Thus, even if a couple has not been blessed with children, when they lovingly and devotedly have sexual relations they become partners in bringing the souls of children into this world. To understand this, we must bear in mind that the process by which souls descend into the world is complicated by many phases and various aspects, which means that several couples can have a part in drawing a single soul into the world (see below, 8:6.)
It is also worth adding that even after a couple has finished having children, by lovingly and joyfully having sexual relations they add life and blessing to all worlds, especially those that are connected to the deepest root of their souls. Thus, any sexual union undertaken in sanctity and passion draws greater illumination and blessing into the souls of their children.
Another important point: A widower who has children and for whom it will be difficult to remarry a woman who is still fertile has a mitzva to marry a woman who will not bear children, for being married is the most wholesome human state. Moreover, he will thus be able to fulfill the mitzva of ona and refrain from sinful thoughts (Yevamot 61b; below, 4:8).
Each and every act of intercourse, when undertaken in sanctity, will have a positive impact. Even if the wife does not conceive, it still has an effect on high and produces a soul. The kabbalists elaborate that this is why it is permissible for a husband to have sexual relations with his wife even when she is pregnant, nursing, menopausal, or infertile. He is not wasting his seed; rather, a holy soul comes into existence as a result…. This is why Avraham could sleep with Sarah even though she was barren. It was not, God forbid, a waste…. For a soul comes into being with every act of intercourse, and the offspring of others are then endowed with these souls. This is the meaning of conversion to Judaism…that is, through the power of the holy thoughts of Avraham during intercourse, the male souls were emanated, and the power of the holy thoughts of Sarah during intercourse emanated female souls. The verse (Bereishit 12:5) that mentions “The souls they [Avraham and Sarah] created in Ḥaran” can now be understood: they literally created them with the power of their intercourse. (Shlah, Sha’ar Ha-otiyot, Kedushat Ha-zivug §402).
This is all because their sexual union was infused with passion and devotion; in the words of Zohar (III 168a), “the passionate cleaving of these two righteous people.” According to Arizal:
Regarding sexual union during the months of pregnancy and nursing, a husband is certainly obligated to fulfill the mitzva of ona at these times. One should not, God forbid, take the position that, on the contrary, this seems like a waste of seed. The idea is this: We know that in the supernal world there are two types of sexual union. The first creates souls, and this not constant. The second, which is constant and unceasing, is to sustain and give life to all the worlds. (Arizal, Sha’ar Ha-mitzvot, Bereishit, p. 7)
- Yosef Ḥayim of Baghdad writes similarly:
The phrase “which yields its fruit in season” (Tehilim 1:3)… is followed by “whose foliage never fades,” meaning that even if a man has sexual relations [with his wife] while she is pregnant and nursing, he “never fades,” [his seed] is not wasted. And whatever sexual activity he continues when his wife is old, after menopause, will find success, for if it does not create souls, it will help sustain and bring life to the worlds, as (Arizal) writes in Sha’ar Ta’amei Ha-mitzvot. (Ben Yehoyada on Ketubot 62b)
Similarly, the Sages said that sexual intercourse during the last trimester is “beneficial for both the woman and the fetus, for as a result the fetus emerges healthy and energetic” (Nidda 31a).