Sahih Muslim
The Book of Pilgrimage (Kitab Al-Hajj)
Book Number: 007 / Hadith Number: 2976
Jabir (Allah be pleased with him) reported: I saw Allah's Apostle (may peace be upon him) flinging pebbles while riding his camel on the Day of Nahr, and he was saying: Learn your rituals (by seeing me performing them), for I do not know whether I would be performing Hajj after this Hajj of mine.