The Messenger of Allah ﷺ used to say salam to his right:As-salamu 'alaykum wa rahmatullah (peace be upon you and the mercy of Allah) , until the whiteness of his right cheek could be seen, and to his left: As-salamu 'alaykum wa rahmatullah (peace be upon you and the mercy of Allah) until the whiteness of his left cheek could be seen.
أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يُسَلِّمُ عَنْ يَمِينِهِ السَّلاَمُ عَلَيْكُمْ وَرَحْمَةُ اللَّهِ حَتَّى يُرَى بَيَاضُ خَدِّهِ الأَيْمَنِ وَعَنْ يَسَارِهِ السَّلاَمُ عَلَيْكُمْ وَرَحْمَةُ اللَّهِ حَتَّى يُرَى بَيَاضُ خَدِّهِ الأَيْسَرِ