Narrated Abu As-Safar:
I heard Ibn ‘Abbas saying, “O people! Listen to what I say to you, and let me hear whatever you say, and don’t go (without understanding), and start saying, ‘Ibn ‘Abbas said so-and-so, Ibn ‘Abbas said so-and-so, Ibn ‘Abbas said so-and-so.’ He who wants to perform the Tawaf around the Ka’ba should go behind Al-Hijr (i.e. a portion of the Ka’ba left out unroofed) and do not call it Al-Hatim, for in the pre-Islamic period of ignorance if any man took an oath, he used to throw his whip, shoes or bow in it.
Sahih Bukhari, Volume 5, Book58, Number 187