21B- Gemara says we need reb yehuda to be doresh semuchin to leatn that its talking about anusas aviv. the gemara asks "how do we know its anusas aviv? MY questions is what else can it be talking about? not eishes aviv thats the pasuk b4. so why do we need a semuchin to teach us something that seems obvious. could it possibly be talking about a woman the father was intimate with, didnt marry, and wasnt an anusa or mefuta? like a common law?
Zev Farkas, Canada
1) Rashi to Devarim 23:1 writes that the verse "and he shall not uncover the Kenaf of his father" refers to marrying the Shomeres Yavam of his father. This is the woman waiting to do Yibum with his father. His father's brother died without children, so the father has to do Yibum with his sister-in-law. This sister-in-law is forbidden to the nephew. Rashi points out that one, anyway, is not allowed to marry his aunt, but the verse prohibiting the "Kenaf Aviv" teaches that if he had relations with her he transgresses two negative commandments. Rashi's source is Yevamos 97a.
2) There is an opinion mentioned in the Shulchan Aruch (Even ha'Ezer 26:1) in the Rema that if a man lives with a woman and she is careful to go to the Mikvah and she observes Taharas ha'Mishpachah, she is permitted and is the "Pilegesh" that is mentioned in the Torah. Another opinion mentioned in the Shulchan Aruch says that this is forbidden and is the "Kadeshah" mentioned in Devarim 23:18. At any rate, it would be difficult to say that the "Kenaf of his father" mentioned in Devarim 23:1 is actually the common-law wife, since this is either a Pilegesh or Kadeshah according to different opinions in Rishonim.