Sahih Muslim Book 7, Hadith Number 2904.

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

Ibn ‘Abbas (At lab be pleased with them) reported: Allah’s Messenger (may peace be upon him) and his Companions came to Mecca and the fever in Medina had weakened them. Thereupon the polytheists (of Mecca) said: There would come to you a people whom the fever has made weak and they have suffered severely from it. They sat in Hatim. Thereupon Allah’s Apostle (may peace be upon him) commanded them to walk quickly in three circuits and walk (in four) between the two corners, so that the polytheists should see their endurance. The polytheists then said (to one another You were under the impression that fever had emaciated them, whereas they are stronger than so and so. Ibn Abbas said: He (the Holy Prophet) did not command them (the Muslims) to walk quickly in all the circuits out of kindness to them.