Musannaf Ibn Abi Shayba 9:1012

Ibn Idris narrated to us, from Dawud ibn Abi Hind, from Muhammad ibn Abi Musa, from Ziyad, who said: I said to my father, "If the wives of the Prophet, may Allah bless him and grant him peace, were to pass away, would it be lawful for him to marry?" He said, "And who would prevent him? Allah made lawful for him a type of women, so he used to marry from among them whomever he wished." Then he recited this verse: "O Prophet, indeed We have made lawful to you your wives to whom..." until he concluded the verse.