Anas bin Malik (may Allah be pleased with him) said: When the Prophet (peace and blessings be upon him) gave his wives the choice and they chose Allah and the Messenger of Allah (peace and blessings be upon him), Allah Almighty restricted him to them and revealed the verse: "Women are not lawful for you after this." [Surah al-Ahzab: 52]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13347