Farat bin Abi 'Abdur Rahman فرات بن أبي عبد الرحمن القزاز · The Book of Forgetfulness (In Prayer)

The Prophet (ﷺ) used to say salam to his right and to his left: As-salamu 'alaykum wa rahmatullah, as-salamu alaykum wa rahmatullah (peace be upon you and the mercy of Allah, peace be upon you and the mercy of Allah) until the whiteness of his cheek could be seen from here, and the whiteness of his cheek from here.