Sahih Muslim Book 7, Hadith Number 3082.

Chapter : The demolishing of the ka’ba and its reconstruction.

‘Abdullah b. Zubair (Allah be pleased with him) reported on the authority of his mother’s sister (‘Aisha) saying that Allah’s Messenger (may peace be upon him) said: ‘Aisha, if your people had not been recently polytheists (and new converts to Islam), I would have demolished the Ka’ba, and would have brought it to the level of the ground and would have constructed two doors, one facing the east and the other one to the west, and would have added to it six cubits of area from Hijr, for the Quraish had reduced it when they rebuilt it.