It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "When the Jews greet you, they say 'As-Saam Alaikum' (i.e., death be upon you) instead of 'As-Salaam Alaikum.' You should also reply with 'Alaik' (i.e., the same to you)." (That is, in response, just say 'Alaik,' meaning 'the same to you.')

Imam Malik, may Allah have mercy on him, was asked: If someone greets a Jew or a Christian, that is, says "As-salamu Alaikum" to him, should he then revoke it? He said: No, rather he should repent and seek forgiveness, because he acted against the command.