Sayyiduna Ibn Mas'ud (may Allah be pleased with him) said: Whatever things I have forgotten, I have forgotten, but I have not forgotten that the Prophet (peace and blessings of Allah be upon him), at the end of the prayer, would turn to the right and to the left saying "As-salamu 'alaykum wa rahmatullah," until the whiteness of his cheeks would be visible.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 4172
Hadith Gradingحکم دارالسلام:صحيح، وهذا إسناد ضعيف لضعف جابر الجعفي.