[Machine] The Messenger of Allah, ﷺ , used to greet by saying "Peace be upon you and the mercy of Allah" with his right hand until the whiteness of his right cheek was visible, and with his left hand until the whiteness of his left cheek was visible. This is a hadith.
أَنَّ رَسُولَ اللهِ ﷺ كَانَ يُسَلِّمُ عَنْ يَمِينِهِ السَّلَامُ عَلَيْكُمْ وَرَحْمَةُ اللهِ حَتَّى يُرَى بَيَاضُ خَدِّهِ الْأَيْمَنِ وَعَنْ يَسَارِهِ السَّلَامُ عَلَيْكُمْ وَرَحْمَةُ اللهِ حَتَّى يُرَى بَيَاضُ خَدِّهِ الْأَيْسَرِ هَذَا حَدِيثٌ