Sahih Bukhari, Chapter: Jihaad (Fighting for the cause of Allah)

I went along with the Prophet (SAW) to Khaibar so as to serve him. (Later on) when the Prophet (SAW) returned he, on seeing the Uhud mountain, said, "This is a mountain that loves us and is loved by us." Then he pointed to Al-Madina with his hand saying, "O Allah! I make the area which is in between Al-Madina's two mountains a sanctuary, as Ibrahim (Abraham) made Makkah a sanctuary. O Allah! Bless us in our Sa and Mudd (i.e. units of measuring)."