It is narrated from Sayyiduna Jabir bin Samurah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "It is sufficient for any one of you, when he has completed his prayer, to place his hand on his thigh and give salam to his brother on his right: 'Al-salamu alaykum wa rahmatullah' (Peace be upon you and the mercy of Allah), and likewise on his left."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1976