Sahih Muslim Book 7, Hadith Number 2889.
Chapter : Excellence of spending the night at Dhi-Tuwa for entering Mecca (for Hajj) and getting into it after a bath and entering during the day.
Ibn Umar (Allah be pleased with him) reported that Allah’s Messenger may peace be upon him) spent the night at Dhi Tuwa till it was dawn and then entered Mecca. ‘Abdullah (b. ‘Umar) himself did like it. And in the narration transmitted by Ibn Sa’id (the words are): Until he observed the dawn prayer. Yahya (another narrator) said: Until it was dawn.