Anas (may Allah be pleased with him) said: When Zaynab's (may Allah be pleased with her) waiting period ended, the Messenger of Allah (peace and blessings be upon him) said to Zayd (may Allah be pleased with him): "Mention marriage to her on my behalf." Zayd (may Allah be pleased with him) said: So I went and said: O Zaynab! Rejoice, the Messenger of Allah (peace and blessings be upon him) has sent me to propose to you. She said: I will not do anything until I consult my Lord. So she went to her place of prayer; then the Qur'an was revealed, and the Messenger of Allah (peace and blessings be upon him) came and entered upon her without permission.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20481