The Book of Pilgrimage (Kitab Al-Hajj)
Muslim :: Book 7 : Hadith 2890
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.