Sahih Muslim 582
Sahih Muslim · Book 5: The Book of Mosques and Places of Prayer · The salam to exit the prayer when one has finished and how it is done
'Amir b. Sa'd reported:
وَحَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ ، أَخْبَرَنَا أَبُو عَامِرٍ الْعَقَدِيُّ ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ جَعْفَرٍ ، عَنْ إِسْمَاعِيلَ بْنِ مُحَمَّدٍ ، عَنْ عَامِرِ بْنِ سَعْدٍ ، عَنْ أَبِيهِ ، قَالَ كُنْتُ أَرَى رَسُولَ اللَّهِ صلى الله عليه وسلم يُسَلِّمُ عَنْ يَمِينِهِ وَعَنْ يَسَارِهِ حَتَّى أَرَى بَيَاضَ خَدِّهِ .
I saw the Messenger of Allah (may peace be open him) pronouncing taslim on his right and on his left till I saw the whiteness of his cheek.