Sunan An-Nasa'i

Jabir said:""Messenger of Allah went out to As-Safa and said.We will start with that with which Allah started. Then he recited: 'Verifly, as-Safa and Al-Marwah (two Mountains in Makkah) are of the symbols of Allah.'"" (Sahih) Chpater 169. Where To Stand On As-Safa