Sahih Muslim Book 7, Hadith Number 2896.

Chapter : Excellence of walking at a quick pace in Tawaf and Umra and on the occasion of first Tawaf in Hajj.

Nafi’ reported on the authority of Ibn Umar (Allah be pleased with them) that Allah’s Messenger (may peace be upon him) walked swiftly from stone to stone in three circuits and walked (normally) in four.