Sahih Muslim
The Book Pertaining to the Excellent Qualities of the Holy Prophet (may Peace be upon them) and His Companions (Kitab Al-Fadail)
Book Number: 030 / Hadith Number: 5742
Simak b. Harb reported: I said to Jabir b. Samura: Did you have the privilege of sitting in the company of Allah's Messenger (may peace be upon him)? He said: Yes, very frequently, and added: He did not stand up (and go) from the place where he offered the dawn prayer until the sun rose, and after the rising of the sun he stood up, and they (his Companions) entered into conversation with one another and they talked of the things (that they did during the Days of Ignorance), and they laughed (on their unreasonable and ridiculous acts). Allah's Messenger (may peace be upon him) smiled only.