Sahih Bukhari Volume 1, Book 2, Hadith Number 18

Narated By Abu Said Al-Khudri : Allah’s Apostle said, “A time will come that the best property of a Muslim will be sheep which he will take on the top of mountains and the places of rainfall (valleys) so as to flee with his religion from afflictions.”

References

Reference: Sahih al-Bukhari 19
In-Book Reference: Sahih al-Bukhari Book 2 Hadith 12