Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) said: We obtained captive women and we used to practise 'azl. We asked the Messenger of Allah (peace and blessings be upon him) about it, and he (peace and blessings be upon him) said: "You do this, you do this, you do this! Any soul that is to come into this world will certainly come."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14309