Sahih Muslim Book 41, Hadith Number 7052.
Chapter : Approach of the Last Hour.
Anas b. Malik reported that a person asked Allah’s Apostle (may peace be upon him): When would the Last Hour come? Thereupon Allah’s Messenger (way peace be upon him) kept quiet for a while. then looked at a young boy in his presence belonging to the tribe of Azd Shanilwa and he said: If this boy lives he would not grow very old till the Last Hour would come to you. Anas said that this young boy was of our age daring those days.