Dear Rabbi, the Talmud (Sotah 9b1) cites from Genesis 4:2 that Cain was born with a twin girl and Abel with 2 twin girls. But I don't see this written in Genesis! Please explain.
AskTheRabbi.org answered:
The source is the Oral Torah which is the Talmud itself! The same narrative appears in the Midrash Rabbah, Bereshit 22 as well.