Sahih Bukhari Volume 007, Book 062, Hadith Number 092B.
Narrated By Anas bin Malik : "Whenever the Prophet passed by (my mother Um-Sulaim) he used to enter her and greet her. Anas further said: Once the Prophet way a bridegroom during his marriage with Zainab, Um Sulaim said to me, "Let us give a gift to Allah's Apostle." I said to her, "Do it." So she prepared Haisa (a sweet dish) made from dates, butter and dried yoghurt and she sent it with me to him. I took it to him and he said, "Put it down," and ordered me to call some men whom he named, and to invite whomever I would meet. I did what he ordered me to do, and when I returned, I found the house crowded with people and saw the Prophet keeping his hand over the Haisa and saying over it whatever Allah wished (him to say). Then he called the men in batches of ten to eat of it, and he said to them, "Mention the Name of Allah, and each man should eat of the dish the nearest to him." When all of them had finished their meals, some of them left and a few remained there talking, over which I felt unhappy. Then the Prophet went out towards the dwelling places (of his wives) and I too, went out after him and told him that those people had left. Then he returned and entered his dwelling place and let the curtains fall while I was in (his) dwelling place, and he was reciting the Verses: 'O you who believe! Enter not the Prophet's house until leave is given you for a meal, (and then) not (as early as) to what for its preparation. But when you are invited, enter, and when you have taken your meals, disperse without sitting for a talk. Verily such (behavior) annoys the Prophet; and he would be shy of (asking) you (to go), but Allah is not shy of (telling you) the Truth.' (33-53) Abu Uthman said: Anas said, "I served the Prophet for ten years."