Sahih Muslim Book 007, Hadith Number 2875.
Chapter : Talbiya of the Apostle (may peace be upon him) and his sacrifice.
Anas (Allah be pleased with him) reported that 'All (Allah be pleased with him) came from the Yemen, and the Apostle (may peace be upon him) said: With (what intention) have you put on Ihram? He said: I have put on Ihram in accordance with the intention with which Allah's Apostle (may peace be upon him) has put on Ihram, whereupon he (the Holy Prophet) said: Had there not been the sacrificial animals with me, I would have put off Ihram (after performing 'Umra). This Hadith is narrated by Salim b. Hayyin with the same chain of transmitters, but with a slight variation of words.