مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2367
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn 'Abbas (رضي الله عنه) said: The Messenger of Allah (ﷺ) circumambulated [the Ka'bah] on his camel, and every time he came to the Corner, he pointed at it and said takbeer.
Musnad Ahmad 2378isnad is saheeh according to the conditions of al-Bukhari]