Sahih Bukhari Volume 8, Book 76, Hadith Number 489.

Narated By Abu Musa : Allah’s Apostle said. “My example and the example of the message with which Allah has sent me is like that of a man who came to some people and said, “I have seen with my own eyes the enemy forces, and I am a naked warner (to you) so save yourself, save yourself! A group of them obeyed him and went out at night, slowly and stealthily and were safe, while another group did not believe him and thus the army took them in the morning and destroyed them.”