The Shulhan Aruch writes at the beginning of the Eben Ha’ezer section (listen to audio recording for precise citation) that a man is obligated to get married and have children. This is the position of the Rambam (Rabbi Moshe Maimonides, Spain-Egypt, 1135-1204), in Hilchot Ishut (chapter 15). Although a wife may, in principle, waive the husband’s obligation of Ona (conjugal rights), the Shulhan Aruch writes that she may not do so before they couple has produced children. Besides the husband’s obligations to his wife, he also bears the obligation of Peru U’rbu – to reproduce – and he must therefore be with his wife even if she does not demand her conjugal rights. (Once the husband has fulfilled the Misva, then the wife is able to waive her Ona rights.)
The Shulhan Aruch adds that the Misva of procreation is of such importance that one may even sell a Torah scroll if this is necessary to obtain funds for an orphan to marry. Selling a Torah scroll is generally forbidden, and Halacha allows such a sale only for the purpose of learning Torah (meaning, paying for Jewish education) or for marriage.
There is a debate between two commentaries to the Shulhan Aruch, the Bet Shemuel (Rabbi Shemuel Feivish, 1630-1700) and the Helkat Mehokek (Rabbi Moshe Lima, 1605-1685), regarding the scope of this Halacha. The Helkat Mehokek ruled that one may sell a Torah scroll for the wedding of a needy orphan boy, but not for a needy orphan girl. The obligation of Peru U’rbu applies only to men, and therefore we should allow selling a Torah scroll only for the marriage of a needy boy, who needs money so he could fulfill his Misva of Peru U’rbu. But we would not, according to this view, sell a Torah scroll to help an orphan girl get married, as she is not included in this obligation. The Bet Shemuel, however, disagrees, noting that there is a separate Misva of "Le’shebet Yesarah," to contribute to the population of the earth, which applies to both men and women. Therefore, even in the case of a girl in need of money to get married, we should go so far as to sell a Torah scroll.
The Shulhan Aruch writes that the Misva for a man to get married takes effect at the age of eighteen. Some authorities understood this to mean that one should get married at the beginning of his eighteenth year, meaning, the day after his seventeenth birthday, but the Bah (Rabbi Yoel Sirkis, Poland, 1561-1640) and others held that this means after the completion of eighteen years. This also appears to be the view of Maran, in Bet Yosef.
Although Misva obligation generally begins at the age of thirteen, it appears that our Sages received a tradition that the Misva to get married and have children does not begin until the age of eighteen. Since a young man has to learn before he assumes the responsibilities of a family, Halacha teaches that one learns for five years after becoming a Bar Misva and only then marry. Nevertheless, the Shulhan Aruch cites from earlier sources that it is a "Misva Min Ha’mubhar" (special Misva) to get married even before the age of eighteen, in order to protect himself from the Yeser Hara (evil inclination). The Tur (Rabbi Yaakob Ben Asher, Germany-Spain, 1275-1349) writes that this applies even before the age of thirteen, but Maran writes in Bet Yosef that it is improper to get married before the age of thirteen.
The Shulhan Aruch writes that one must get married by the time he reaches the age of twenty, and if somebody does not marry by the age of twenty, then, strictly speaking, the Bet Din (Rabbinical Court) forces him to marry. Nowadays, however, as the Shulhan Aruch adds, Bet Din does not force people to marry, or use coercive measures against married couples that have not borne children.
The Shulhan Aruch’s rulings on this subject demonstrate the supreme importance that Halacha affords to marriage and procreation, and how seriously our tradition views the obligation to get married and beget children in order to build the next generation of Jews.
