أَخْبَرَنَا زَيْدُ بْنُ أَخْزَمَ، عَنِ ابْنِ دَاوُدَ، - يَعْنِي عَبْدَ اللَّهِ بْنَ دَاوُدَ الْخُرَيْبِيَّ - عَنْ عَلِيِّ بْنِ صَالِحٍ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي الأَحْوَصِ، عَنْ عَبْدِ اللَّهِ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ كَأَنِّي أَنْظُرُ إِلَى بَيَاضِ خَدِّهِ عَنْ يَمِينِهِ ‏"‏ السَّلاَمُ عَلَيْكُمْ وَرَحْمَةُ اللَّهِ ‏"‏ ‏.‏ وَعَنْ يَسَارِهِ ‏"‏ السَّلاَمُ عَلَيْكُمْ وَرَحْمَةُ اللَّهِ ‏"‏ ‏.‏

It was narrated from 'Abdullah that: The Prophet (PBUH) said: "It is as if I can see the whiteness of his cheek, saying to his right: As-salamu 'alaykum wa rahmatullah (peace be upon you and the mercy of Allah) and to his left: As-salamu 'alaykum wa rahmatullah (peace be upon you and the mercy of Allah)." (Sahih Translation Not Available

Book Ref: Sunan An Nisai Book 13 Hadith 1322
Web Ref:  Sunan An Nisai Vol 2 Book 13 Hadith 1323