Sahih Muslim
The Book of Faith (Kitab Al-Iman)
Book Number: 001 / Hadith Number: 384
Anas b. Malik reported: The Messenger of Allah (may peace be upon him) said: I will come to the gate of Paradise on the Day of Resurrection. and would seek its opening. and the keeper would say: Who art thou? I would say: Muhammad. He would then say: It is for thee that I have been ordered, and not to open it for anyone before thee.