The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 1210
Ibn 'Abbas reported: We knew the finishing of the prayer of the Messenger of Allah (may peace be upon him) through takbir. 'Amr (b. Dinar) said: I made a mention of it to Abu Mas'ud. hue he rejected it and said: I never narrated it to you. 'Amr said: He did narrate it before this.