Sayyiduna Urwah bin Mudarris bin Harithah bin Lam al-Ta'i (may Allah be pleased with him) said: I came to the Messenger of Allah (peace and blessings be upon him) at the standing place of Muzdalifah and said: "O Messenger of Allah! I have come to you from the mountain of Tayyi'. I have wearied my mount and exhausted myself. By Allah! On every mountain I came down at, I stood there. So has my Hajj been accomplished, O Messenger of Allah?" The Messenger of Allah (peace and blessings be upon him) said: "Whoever prays the morning prayer with us at Muzdalifah, having already come to Arafat before that, by night or by day, he has removed his grime (completed his rites) and his Hajj is complete."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14458