Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah
Narrated ‘Abdullah bin ‘Umar (Radi-Allahu ‘anhu):
Allah’s Apostle (Sallallahu ‘Alaihi Wa Sallam) said, “When the Jews greet you, they usually say, ‘As-Samu ‘alaikum (Death be on you),’ so you should say (in reply to them), ‘Wa’alaikum (And on you).”
Bukhari Vol. 8 : No. 274