these are the years of the generations, i.e., the allotted lifespan that is preordained for each individual before birth. If he is deserving, God completes his allotted lifespan. If he is not deserving, God reduces his lifespan; this is the statement of Rabbi Akiva. Rabbi Akiva assumes one cannot outlive one’s preordained allotted lifespan. The Rabbis say: If he is deserving, God adds years to his lifespan. If he is not deserving, God reduces his lifespan. According to the Rabbis, Isaiah’s prophecy is referring to one who deserved to have extra years added to his allotted lifespan, and the verse in the Torah is referring to one who deserved to merely complete his lifespan.

The Rabbis said to Rabbi Akiva: How can you claim that one cannot outlive one’s allotted lifespan when there is a verse that states that Isaiah prophesied to Hezekiah as Hezekiah lay on his deathbed: “And I will add unto your days fifteen years”? Rabbi Akiva said to them: Those additional years that God added to his lifespan are from his own allotted lifespan. When Hezekiah sinned God decreed that his lifespan be shortened, but when he repented God allowed him to live out those years. Know that this is so, as a prophet during the reign of King Jeroboam stood and prophesied: “Behold, a son shall be born unto the House of David, Josiah is his name” (I Kings 13:2). Josiah was the grandson of Manasseh, Hezekiah’s son, and at the time Hezekiah lay on his deathbed, Manasseh had not yet been born. Evidently, Hezekiah’s preordained allotted lifespan had still not been completed.

And what would the Rabbis respond to Rabbi Akiva’s proof? They could counter: Is it written that Josiah was to be born specifically from the descendants of Hezekiah? It is written only that he would be born “unto the House of David,” so he could be born either from the descendants of Hezekiah or from a different person of the House of David. Accordingly, no proof concerning Hezekiah’s allotted lifespan can be deduced from that verse.

§ The mishna details the prohibition with regard to one’s wife’s sister in various cases: If a man’s wife died, he is permitted to her sister; if his yevama died, he is permitted to her sister. Rav Yosef said: Here Rabbi Yehuda HaNasi taught an unnecessary mishna, since the prohibition with regard to one’s wife’s sister and the fact that the prohibition exists only in the lifetime of one’s wife is stated explicitly in the Torah, and there is no additional novelty in this mishna’s ruling.

MISHNA: Rabban Gamliel says: A bill of divorce [get] is not effective when given after a bill of divorce was previously given to a yevama. Once a yevama receives a bill of divorce from a yavam, no bill of divorce given by that yavam to her rival wife or a bill of divorce given to her by a different yavam is of any effect. And levirate betrothal is not effective after a previous levirate betrothal was performed, and intercourse with a second yevama is not effective after intercourse with the first one, and ḥalitza is not effective after ḥalitza was previously performed. But the Rabbis say: A bill of divorce is effective when given after a bill of divorce, and levirate betrothal is effective after levirate betrothal, but nothing is effective after intercourse or after ḥalitza. If a yavam has relations with the yevama or performs ḥalitza with her, no other action performed afterward is effective, whether performed by that yavam toward a different yevama or by any yavam with the original yevama.

The mishna elaborates: How do these laws work in practice? If a yavam performed levirate betrothal with his yevama, and he later gave her a bill of divorce, she nevertheless requires ḥalitza from him. The bill of divorce does not fully exempt her from levirate marriage, as the levirate bond remains intact. If he performed levirate betrothal and then ḥalitza, she requires a bill of divorce from him in order to cancel the levirate betrothal. If the yavam performed levirate betrothal and then engaged in intercourse with the yevama, this is the way to perform levirate marriage in accordance with its mitzva, as the Sages instituted this as the proper procedure for a yavam to perform levirate marriage.

If the yavam gave the yevama a bill of divorce and afterward performed levirate betrothal with her, she requires another bill of divorce to cancel the levirate betrothal, as well as ḥalitza to nullify the levirate bond. If he gave her a bill of divorce and then engaged in intercourse with her, she requires a bill of divorce to cancel the betrothal that took place via intercourse, and ḥalitza to nullify the levirate bond; the intercourse did not affect the levirate bond because once he gave her a bill of divorce she was forbidden to him. If he gave her a bill of divorce and performed ḥalitza, nothing is effective after ḥalitza, as the levirate bond was completely nullified.

Similarly, if he performed ḥalitza with her and then either performed levirate betrothal, or gave a bill of divorce, or engaged in intercourse with her; alternatively, if he engaged in intercourse with her and then either performed levirate betrothal, or gave a bill of divorce, or performed ḥalitza after they engaged in relations, nothing is effective after ḥalitza or intercourse. Any action performed afterward is unrelated to the levirate bond.