Musannaf Ibn Abi Shaybah 3082 — Those who used to give two salams

Ibrahim bin Suwayd said: Alqamah would give the salam to the right, saying 'As-salamu alaykum wa rahmatullah' (Peace be upon you and the mercy of Allah), and then give the salam to the left, saying 'As-salamu alaykum wa rahmatullah'. And al-Aswad, when giving the salam to the right, would say: 'As-salamu alaykum wa rahmatullahi wa barakatuh' (Peace be upon you, and the mercy of Allah and His blessings), and when giving the salam to the left he would say: 'As-salamu alaykum wa rahmatullahi wa barakatuh'.