Abd al-Rahman al-Yahsubi (may Allah have mercy on him) narrates from Sayyiduna Wa'il bin Hujr (may Allah be pleased with him); he said: I saw the Prophet (peace and blessings be upon him) giving the salam to the right and to the left until the whiteness of his cheek could be seen.
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18325