Anas bin Malik reported,

I invited the Muslims to the wedding feast of the Messenger of Allah ﷺ on the morning he consummated his marriage with Zaynab bint Jahsh. He fed the Muslims their fill of bread and meat.Then he went out, as was his custom, and came to the chambers of his wives, greeting them, and they prayed for him. Then he returned to his house with me accompanying him. When he reached the house, there were two men engaged in conversation in a corner of the house. When he saw them, he turned away. When the two men noticed that the Prophet ﷺ had turned away from his house, they got up quickly and left. I do not recall whether I informed him that they had left or someone else did. He then returned to his home and let down the curtain between him and me, and the verse of the hijab was revealed.

حدثنا ابن أبي عدي عن حميد

عن أنس قال

دعوت المسلمين إلى وليمة رسول الله ﷺ صبيحة بنى بزينب بنت جحش فأشبع المسلمين خبزا ولحما قال ثم رجع كما كان يصنع فأتى حجر نسائه فسلم عليهن فدعون له قال ثم رجع إلى بيته وأنا معه فلما انتهى إلى البيت فإذا رجلان قد جرى بينهما الحديث في ناحية البيت فلما بصر بهما ولى راجعا فلما رأى الرجلان النبي ﷺ قد ولى عن بيته قاما مسرعين فلا أدري أنا أخبرته أو أخبر به ثم رجع إلى منزله وأرخى الستر بيني وبينه وأنزلت آية الحجاب