'A'isha (may Allah swt please with her) reported that a group of Jews came to Allah's Messenger (may peace be upon him) and sought his audience and said: As-Sam-u-'Alaikum. A'isha said in response: As-Sim-u-'Alaikum (death be upon you) and curse also, whereupon Allah's Messenger (may peace be upon him) said: 'A'isha, verily Allah loves kindness in every matter. She said: Did you hear what they said? Thereupon he said: Did you not hear that I said (to them): Wa 'Alaikum (same to you).

Muslim :: Book 26 : Hadith 5384