The Book of Pilgrimage (Kitab Al-Hajj)
Muslim :: Book 7 : Hadith 2844
Anas (Allah be pleased with him) said: I heard Allah's Apostle (way peace be upon him) pronouncing Talbiya for both Hajj and Umra. Bakr (one of the narrators) said: I narrated it to Ibn 'Umar, whereupon he said: He (the Holy Prophet) pronounced the Talbiya for Hajj alone. I met Anas and narrated to him the words of Ibn 'Umar, whereupon he said: You treat us not but only as children. I heard Allah's Messenger (may peace be upon him) pronouncing Talbiya both for 'Umra and Hajj.