Sahih al-Bukhari 5166

It is related from Anas ibn Malik that he was ten years old whet he Prophet, may Allah bless him and grant him peace, came to Madina. He said, "My mother and my aunts kept asking me to serve the Prophet, may Allah bless him and grant him peace, and I served him for ten years. I was twenty when the Prophet, may Allah bless him and grant him peace, died. I am the one who knows best about the business of the screen and when it was revealed. The first of what was revealed was on the wedding night of the Messenger of Allah , may Allah bless him and grant him peace, with Zaynab bint Jahsh. In the morning, the Prophet, may Allah bless him and grant him peace, was a groom and he invited people who had some food and then went out. A group of them remained with the Prophett, may Allah bless him and grant him peace, for a long time. The Prophet, may Allah bless him and grant him peace, got up and went out and I went out with him so that they would go out. The Prophet, may Allah bless him and grant him peace, walked and so did I, and he went to the threshold of 'A'isha's room. Thinking that they had left, he went back and I went with him. He entered where Zaynab was and they were still sitting there and had not left. So the Prophet, may Allah bless him and grant him peace, went back and I went with him as far as the threshold of 'A'isha's room. Thinking that they had left, he went back and I went with him, and they had left. The Prophet , may Allah bless him and grant him peace, put a curtain between me and him and the Screen (Hijab) was revealed."