Ubaydullah bin al-Qibtiyyah said: I heard Sayyiduna Jabir bin Samurah (may Allah be pleased with him) say: When we prayed behind the Prophet (peace and blessings be upon him), we would say: As-salamu alaykum, as-salamu alaykum (and Mis'ar pointed with his hand to his right and to his left). So he (peace and blessings be upon him) said: "What is the matter with these people, that they raise their hands like the tails of unruly horses? Is it not enough for one of you, or for one of them, to place his hand on his thigh, then give salam to his brother on his right and his left?"
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1823