Sahih Muslim Book 41, Hadith Number 7051.

Anas reported that a person asked Allah’s Messenger (may peace be upon him) as to when the Last Hour would come. He had in his presence a young boy of the Ansar who was called Mahammad, Allah’s Messenger (may peace be upon him) said: If this young boy lives, he may not grow very old till (he would see) the Last Hour coming to you.