Musnad Ahmad 31:654

Yazid narrated to us, Hisham informed us, from Muhammad, from his brother Ma'bad ibn Sirin, who said: I said to Abu Sa'id al-Khudri: Did you hear anything from the Messenger of Allah, peace and blessings of Allah be upon him, regarding *al-'azl* (coitus interruptus)? He said: Yes. We asked the Messenger of Allah, peace and blessings of Allah be upon him, about *al-'azl*, and he said: "And what is it?" We said: A man has a nursing wife, and he has intercourse with her, but he dislikes that she should become pregnant, so he practices *'azl* with her. And a man has a slave girl, and he has no wealth other than her, and he has intercourse with her, but he dislikes that she should become pregnant, so he practices *'azl* with her. He said: "It does not matter if you do not do it, for it is only the decree."