سنن النسائي

It was narrated from 'Abdur-Rahman bin Al-Aswad from his father-and Alqamah-that: Abdullah said: "I saw the Messenger of Allah (ﷺ) say the Takbir every time he went down and got up, or stood or sat; he said the Salam on his right and his left: 'As-salamu alaykum wa rahmatulah (peace be upon you and the mercy of Allah ),' until the whiteness of his cheek could be seen." He said: "And I saw Abu Bakr and 'Umar, may Allah (SWT) be pleased with them both, doing the same."