Musannaf Ibn Abi Shayba 3:6043

Hushaym narrated to us, he said: Al-Kalbi informed us, from Abu Salih, from Ibn Abbas, who said: When the [verse regarding the] marriage of Zaynab was revealed, Zayd ibn Harithah set out until he sought permission to enter upon Zaynab. She said: "What do I have to do with Zayd?" He said: So he sent word to her and said: "I am the messenger of the Messenger of Allah, may Allah bless him and grant him peace, to you." He said: So she gave him permission, and he gave her the glad tidings that Allah had married her to His Prophet, may Allah bless him and grant him peace. He said: So she fell down prostrating to Allah in gratitude.