Narrated Anas bin Malik:
"I was with the Prophet (ﷺ), and he came to the door of a woman with whom he had consummated marriage, and some people were with her. So, he left to fulfill his need, and was prevented (from her). Then he came back, and some people were still with her. Then he left to fulfill his need and came back and they had gone." He said: "So, I mentioned that to Abu Talhah and he said: 'If it is as you say, something shall surely be revealed concerning this,' and the Verse of Hijab was revealed.
English reference: Vol. 5, Book 44, Hadith 3217
Arabic reference: Book 47, Hadith 3523