Abu Dawud
The Rites of Hajj
Book Number: 004 / Hadith Number: 1717
Narated By Aqra' ibn Habib : Ibn Abbas said: Aqra' ibn Habis asked the Prophet (pbuh) saying: Apostle of Allah hajj is to be performed annually or only once? He replied: Only once, and if anyone performs it more often, he performs a supererogatory act.