Mishkat al-Masabih 10 The Rites of Pilgrimage كتاب المناسك 64

وَعَنْهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ طَافَ بِالْبَيْتِ عَلَى بَعِيرٍ كُلَّمَا أَتَى عَلَى الرُّكْنِ أَشَارَ إِلَيْهِ بِشَيْءٍ فِي يدِه وكبَّرَ. رَوَاهُ البُخَارِيّ

He said that God’s messenger went round the House on a camel, and as often as he came to the corner he pointed to it with something in his hand and said, “God is most great.” Bukhari transmitted it.