When the mighty army of King Sennacherib of Assyria besieged Jerusalem, King Ḥizkiyahu of Yehuda fell ill, as we read:
In those days, Ḥizkiyahu fell dangerously ill. The prophet Yeshayahu, son of Amotz, came and said to him, “Thus said the Lord, ‘Set your affairs in order, for you are going to die; you will not live.’” (Yeshayahu 38:1)
Even years before that, Ḥizkiyahu had been aware that the Kingdom of Assyria presented a clear and present danger to his kingdom, for as a result of increasing sinfulness, Assyria had already subjugated the Kingdom of Yisrael and exiled the ten tribes from the land (2 Melakhim, ch. 17). In order to avert calamity, Ḥizkiyahu ordered the entire nation to repent and to strengthen their allegiance to Torah:
He stuck a sword by the entrance of the beit midrash and said, “Anyone who does not study Torah will be stabbed with this sword.” They searched from Dan to Be’er Sheva and did not find a single ignoramus; from Gevat to Antipatris and did not find a single boy or girl, man or woman, who was not thoroughly versed in the laws of purity and impurity. (Sanhedrin 94b)
It was at this difficult time, when the catastrophe Ḥizkiyahu feared was imminent, when the Assyrian army had already besieged Jerusalem, and when he himself lay ill, that the prophet came to him with the terrible message, “Set your affairs in order, for you are going to die; you will not live.” The Sages explain: “You are going to die” in this world, and “you will not live” in the next world. Ḥizkiyahu cried out in protest, “What sin have I committed that I have been sentenced to excision from this world and from the next?” The prophet replied, “You did not engage in procreation.” Ḥizkiyahu responded, “But it was made known to me through divine inspiration that my children would not be virtuous.” The prophet replied, “Why do you involve yourself in the secrets of the Merciful One? You do what you were commanded to do, and God will do what is right in His eyes.” Ḥizkiyahu then realized that he had sinned. He asked Yeshayahu for his daughter’s hand in marriage, hoping that his own merit plus the merit of Yeshayahu might help him have virtuous children. The prophet responded, “Your fate has already been sealed.” Ḥizkiyahu replied, “Son of Amotz, finish your prophecy and leave! For I learned from my father’s father (King David) that even if a sharp sword is resting upon one’s neck, one should not stop begging for mercy” (Berakhot 10a).
Then, “Ḥizkiyahu turned his face to the wall and prayed to the Lord. ‘Please, O Lord,’ he said, ‘remember how I have walked before You sincerely and wholeheartedly, and have done what is pleasing to You.’ And Ḥizkiyahu wept profusely” (Yeshayahu 38:2-3). God heard him and commanded Yeshayahu to inform Ḥizkiyahu that He had added another fifteen years to his life. Additionally, God would save him from Assyria’s army. In fact, in the middle of the night, an angel of God struck down all of Sennacherib’s soldiers, and Jerusalem was saved. Ḥizkiyahu went on to marry Yeshayahu’s daughter, and they had a son named Menasheh. Ḥizkiyahu’s fears were realized; Menasheh, who ruled after Ḥizkiyahu, acted so wickedly in the eyes of God – worshiping idols and spilling much innocent blood – that God decreed that the First Temple would be destroyed (2 Melakhim ch. 19-21). Nevertheless, the mitzva of procreation remained in full force, for it is the foundation for the continued existence of the world. Even in the case of Ḥizkiyahu, his wicked son Menasheh carried on the Davidic dynasty, from which ultimately the Messiah, descendant of David, will be born; may he come speedily in our time.
Although we learn of a great Tanna, Ben Azzai, who never married and did not fulfill the mitzva of procreation. The Talmud relates that Ben Azzai extrapolated from the biblical verses that if one does not engage in procreation, “it is as if he spills blood and diminishes the divine image.” The Sages said to Ben Azzai, “Some preach well and practice well; some practice well but do not preach well; and then there are those like you, who preach well but do not practice what they preach!” Ben Azzai responded, “What can I do? My soul longs for Torah. The world can be sustained by others” (Yevamot 63b). In fact, halakha accepts Ben Azzai’s position. If someone’s soul longs for Torah, and he spends his entire life studying with tremendous dedication, as a result of which he never marries, he has not sinned, as long as his sexual desire does not overcome him (MT, Laws of Marriage 15:3; SA EH 1:4). However, the language here is precise: he has not sinned, but le-khatḥila, it is not proper to behave this way (Naḥalat Tzvi; Taz ad loc. 6).
We see that there is only one mitzva one can engage in and thereby, under pressing circumstances, abstain from the mitzva of procreation – the mitzva of Torah study. This is because Torah study itself adds life to the world. The fact is that although Ben Azzai did not engage in procreation, he delved deeply into the great importance of the mitzva and expounded upon its great value. Certainly, many children were born as a result of his teachings. In contrast, when Ḥizkiyahu wished to stipulate his performance of the mitzva on having children who would not be wicked, he was negating the sacred principle underlying the mitzva, which expresses the absolute value of life. This is why he would have been subject to terrible punishment in both this world and the next. We learn from this that life is the supreme value, and even the wicked can repent. Furthermore, even if they do not repent, the righteous can learn from their mistakes. However, when one disregards the mitzva altogether, he uproots everything and denies the value of God-given life in this world.
The explanation seems to be that since the mitzva of procreation is contingent upon marriage, and marriage entails being attentive and emotionally available to another person so that one can form a loving relationship with a spouse. Ben Azzai knew himself and realized that his intense commitment to Torah study would not allow him to adequately satisfy the needs of his wife. Therefore, he did not marry. Other mitzvot, however, do not require emotional investment, and therefore can be fulfilled even if one’s mind is still engaged in Torah study. See Sota 49a, which states, “When Ben Azzai died, that was the end of the unceasing learners.” Someone like Ben Azzai also knew that his sex drive would not overpower him. Some poskim have written that no one can emulate Ben Azzai nowadays (Ritva and Birkei Yosef).