Usamah bin Zayd (may Allah be pleased with him) narrates that he set off with the Prophet (peace and blessings be upon him) on the evening of Arafah. Then the Prophet (peace and blessings be upon him) reached the narrow pass, made his mount kneel and relieved himself, then came and began to perform ablution while Usamah poured water for him. Usamah said: O Messenger of Allah, it is time for the prayer. He (peace and blessings be upon him) said: "The place of prayer is ahead of you."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 383