תלמוד על כריתות 3:5

There, we have stated¹²⁰Keritut Mishnah 3:5. The Mishnah speaks of the grandfather’s grandson’s daughter’s daughter who was married to his brother. If that brother dies without issue, the widow is forbidden to her great-grandfather by a secondary prohibition. If the old man marries her in levirate instead of having ḥalîṣah as required, since the prohibition is rabbinic she is married and, if the son sleeps with her, Rebbi Yose the Tanna declares him guilty both for his granddaughter and his father’s wife, committing two sins in one act.: “Rebbi Yose says, if the grandfather transgressed and married her.” What did he transgress? He transgressed the words of the Sopherim¹²¹Three generations are biblically forbidden. She would be secondarily forbidden to the father. Since the Mishnah does not mention the father but “the old man”, generally interpreted as “grandfather”, this is one generation more than that spelled out in the Tosephta. Does this support R. Ḥanin that these prohibitions are unlimited in the number of generations?. Rebbi Yose in the name of Rebbi Abbahu, he asked Rebbi Joḥanan: Does this mean that secondary prohibitions have no limit? He said to him, did we learn “secondaries to secondaries”? No. Secondaries to the words of the Torah, and all of them because of his son’s daughter-in-law¹²²Rebbi Yose the Tanna does not refer to the first part of the Mishnah speaking of a granddaughter but has a new case where the woman was the son’s daughter-in-law before marrying the father’s brother who is permitted to her.. Rebbi Ḥizqiah in the name of Rebbi Jonah, Rebbi Abbahu did not say so, but Rebbi Eleazar asked Rebbi Joḥanan, did we not learn of eight secondaries, and here they are nine! But all of them because of his son’s daughter-in-law¹²³Since this case is the root of all secondary prohibitions it was not spelled out before; Babli Yebamot 21b..