Saying Takbir Upon Reaching the Black Stone

((طَافَ النَّبيُّ صلى الله عليه وسلم بِالْبَيْتِ عَلَى بَعِيرٍ كُلَّمَا أَتَى الرُّكْنَ أَشَارَ إِلَيْهِ بِشَيْءٍ عِنْدَهُ وَكَبَّرَ)).

The Prophet (peace and blessings of Allah be upon him) circled the House [the Ka'bah] on a camel; every time he came to the corner [the Black Stone], he pointed to it with something he had with him and said the Takbir (Allahu Akbar).