Sahih Muslim
The Book on Salutations and Greetings (Kitab As-Salam)
Book Number: 026 / Hadith Number: 5386
'A'isha reported that some Jews came to Allah's Apostle (may peace be upon him) and they said: Abu'l-Qasim (the Kunya of the Holy Prophet), as-Sam-u-'Alaikum, whereupon he (the Holy Prophet) said: Wa 'Alaikum. A'isha reported: In response to these words of theirs, I said: But let there be death upon you and disgrace also, whereupon Allah's Messenger (may peace be upon him) said: 'A'isha, do not use harsh words. She said: Did you hear what they said? Thereupon he (the Holy Prophet) said: Did I not respond to them when they said that; I said to them: Wa'Alaikum (let it be upon you).