Sahih Bukhari, Chapter: Pilgrimage (Hajj)

Salim bin 'Abdullah's father said, "The Prophet said that while resting in the bottom of the valley at Mu'arras in Dhul-Hulaifa, he had been addressed in a dream: 'You are verily in a blessed valley.' " Salim made us to dismount from our camels at the place where 'Abdullah used to dismount, aiming at the place where Allah's Apostle had rested and it was below the Mosque situated in the middle of the valley in between them (the residence) and the road.