Musnad Ahmad 941:29

Abu Abd al-Rahman al-Muqri narrated to us, Haywah narrated to us, Ayyash ibn Abbas informed me that Abu al-Nadr narrated to him, from Amir ibn Sa’d ibn Abi Waqqas, that Usamah ibn Zayd informed his father, Sa’d ibn Malik, he said: He said to him: A man came to the Prophet, peace and blessings of Allah be upon him, and said: "I practice *azl* (coitus interruptus) with my wife." He said: "Why?" He said: "Out of pity for her child, or her children." He said: "If it is for that, then do not. That does not harm the Persians or the Romans." *** Haytham narrated to us, he said: Abdullah said: And I heard it myself from al-Haytham ibn Kharijah, Rushdin ibn Sa’d narrated to us, from Uqayl, from Ibn Shihab, from Urwah ibn al-Zubayr, from Usamah ibn Zayd, from the Prophet, peace and blessings of Allah be upon him: That when Gabriel, peace be upon him, descended upon the Prophet, peace and blessings of Allah be upon him, he taught him the ablution (*wudu*). When he finished his ablution, he took a handful of water and sprinkled it toward the private part. He said: "And the Prophet, peace and blessings of Allah be upon him, used to sprinkle [water] after his ablution."