Sahih Muslim | Book 8 | Hadith Number 3381

Narrated by Abu Sa'id al-Khudri (Allah be pleased with him)
Abu Sa'id al-Khudri (Allah be pleased with him) reported that Allah's Messenger (may peace be upon him) was asked about 'azl, whereupon he said: The child does not come from all the liquid (semen) and when Allah intends to create anything nothing can prevent it (from coming into existence).