Musnad Ahmad 31:555

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from 'Ata' ibn Yazid al-Laythi, from Abu Sa'id al-Khudri, who said: The Messenger of Allah (peace and blessings of Allah be upon him) was asked about *al-'azl* (coitus interruptus). He said: "Do you really do that?" They said: "Yes." He said: "It does not matter if you do not do it, for Allah the Exalted has not decreed for a soul that He will create it, but it will come to be."