مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1484
Musnad Abu Ishaq Sa'd bin Abi Waqqas
It was narrated from ‘Amir bin Sa"d, that his father said The Messenger of Allah (ﷺ) used to - Abu Sa’eed said: I saw the Messenger of Allah (ﷺ) - say salam to his right (turning so much) that the whiteness of his cheek could be seen, and to his left (turning so much) that the whiteness of his cheek could be seen.
Musnad Ahmad 1484lts isnad is Sahih, Muslim (582)]