Abu Dawud Book 30, Hadith Number 4254.
Chapter : Concession for living in the desert during the period of commotion and trial.
Narated By Abu Sa’id al-Khudri : The Apostle of Allah (PBUH) said: A Muslim’s best property will soon be sheep which he takes to the top of mountains and the places where the rain falls, fleeing with his religion from civil strife (fitnah).