Sahih Muslim Book 7, Hadith Number 2907.

Chapter : Excellence of touching the two corners (Rukunain al- Yamaniyain) in Tawaf.

Salim reported on the authority of his father (Allah he pleased with him) that Allah’& Messenger (tinny peace be upon him) did not touch any of the corners of the House, except that of Black Corner (in which the Black Stone is embedded and that (portion) near it, towards the houses of the tribe of jumuhi.