It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that when the Prophet (peace and blessings be upon him) married Sayyidah Zaynab (may Allah be pleased with her), (my mother) Umm Sulaym (may Allah be pleased with her) sent "hays" (a sweet dish of dates, ghee and cheese) in a stone vessel. Anas (may Allah be pleased with him) says: The Prophet (peace and blessings be upon him) said to me: "Go and invite (to the meal) any Muslim you meet." I went, and whoever I met I invited. The Prophet (peace and blessings be upon him) placed his blessed hand on the food, made supplication, and recited what Allah willed. Then the people would eat and leave, until a group remained sitting in the house. The Prophet (peace and blessings be upon him) felt shy of them, while they were engaged in lengthy conversation; so the Messenger of Allah (peace and blessings be upon him) went out and left them in the house. Then Allah Almighty revealed this verse: [Surah al-Ahzab: 53] "O you who believe, do not enter the houses of the Prophet unless permission is given to you for a meal, without waiting for its preparation," meaning: do not sit waiting for its time; until he reached: "That is purer for your hearts and their hearts." This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.