سنن ابن ماجه

It was narrated from Muhammad bin Munkadir: that he heard Jabir bin 'Abdullah say: “The Jews used to say that if a man has intercourse with a woman in her vagina from the back, the child would have a squint. Then Allah, Glorious is He, revealed: 'Your wives are a tilth for you, so go to your tilth, when or how you will.' ”