Mishkat al-Masabih 951 — The method of salām, as narrated by Ibn Mājah

‘Abdallah b. Mas'ud said that God’s Messenger used to turn to the right when giving the salutation, “Peace and God’s mercy be upon you,” so that the whiteness of his right cheek could be seen; also to the left when giving the salutation, “Peace and God’s mercy be upon you,” so that the whitness of his left cheek could be seen. Abu Dawud, Tirmidhi and Nasa’i transmitted it, but Tirmidhi did not mention, “So that the whiteness of his cheek could be seen.” Ibn Majah transmitted it from ‘Ammar b. Yasir.