Sifrei Devarim 248

¹(Devarim 23:3) "A mamzer may not come into the congregation of the L-rd." (" mamzer " =) " mum zar " ("a foreign blemish" [i.e., a blemish resulting from "foreign" (i.e., non-permitted) relationships]), whether a man or a woman. ²Who is a " mamzer "? All kin who are subsumed in "may not come." These are the words of R. Akiva. For it is written ( Ibid . 1) "A man shall not take the wife of his father and he shall not uncover the lap of his father … (3) "A mamzer may not come, etc." Just as "the wife of his father" is distinct in being kin and subsumed in "may not come," and the child is a mamzer , so, in all who are thus characterized, the child is a mamzer . ³Shimon Hatemani says: All who are liable to kareth (cutting-off) at the hands of heaven — the child is a mamzer , it being written "A man shall not take the wife of his father … A mamzer may not come, etc." Just as "the wife of his father" is distinct in being liable to kareth at the hands of heaven and the child is a mamzer , so, in all who are thus characterized, the child is a mamzer . ⁴R. Yehoshua says: All who are liable to judicial death penalty — the child is a mamzer , it being written "A man shall not take the wife of his father … A mamzer may not come, etc." Just as "the wife of his father" is distinct in being subject to judicial death penalty and the child is a mamzer , so, in all who are thus characterized, the child is a mamzer . ⁵"even the tenth generation": It is written here "the tenth generation," and below (4) (in respect to an Amoni and a Moavi) "the tenth generation." Just as "the tenth generation" there is for all time, so, "the tenth generation" here.