Maliks Muwatta Book 20, Hadith Number 179.

Yahya related to me from Malik from Hisham ibn Urwa that his father said, “Someone who does not stand at Arafa on the night of Muzdalifa before the dawn breaks has missed the hajj, and some one who stands at Arafa on the night of Muzdalifa before the dawn breaks has caught the hajj.

Malik said, about a slave freed during the wuquf at Arafa, “His standing does not fulfil for him the hajj of Islam, except if he was not in ihram and then he went into ihram after he was freed and he stood at Arafa that same night before the dawn broke in which case that is enough for him. If, however, he did not go into ihram until after the dawn had broken, he is in the same position as someone who misses the hajj by not catching the standing at Arafa before the breaking of the dawn on the night of Muzdalifa, and he will have to do the hajj of Islam later.”