Sahih Muslim Book 7, Hadith Number 2868.

Chapter : Saying of people to Ibn ‘Abbas: What to this religious verdict of yours that has engaged the attention of the people?

Abu Hassan reported: It was said to Ibn ‘Abbas (Allah be pleased with them) that this affair had engaged the attention of the people that he who circumambulates the House was permitted to circumambulate for Umra (even though he was in a state of Ihram for Hajj), whereupon he said: That is the Sunnah of your Apostle (may peace be upon him), even though you may not approve of it.