Sahih Muslim Book 7, Hadith Number 2890.

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.

Nafi’ reported that Ibn Umar (Allah be pleased with them) did not enter Mecca without spending the night at Dhi Tawu until it was dawn, when he took a bath, and then entered Mecca in the morning, and made a mention that Allah’s Apostle (may peace be upon him) did that.