(a) It is narrated from Abu Razin that Sayyiduna Ali (may Allah be pleased with him) gave the salam to his right and to his left, then stood up.
(b) Mughirah narrated this same report from Abu Razin, and in it is that he said: 'Salamun alaykum, salamun alaykum' (Peace be upon you, peace be upon you).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2984