The Book Pertaining to the Excellent Qualities of the Holy Prophet (may Peace be upon them) and His Companions (Kitab Al-Fada'il)
Muslim :: Book 30 : Hadith 5690
'Abdullah reported Allah's Messenger (may peace be upon him) as saying; I shall be there at the Cistern before you, and I shall have to contend for some people, but I shall have to yield. I would be saying: My Lord, they are my friends, they are my friends, and it would be said: You don't know what innovations they made after you.