صحيح البخاري
From Sahih Bukhari (Hadith 6928):
Narrated Ibn `Umar:Allah's Messenger (ﷺ) said, "When the Jews greet anyone of you they say: 'Sam'Alaika (death be upon you); so you should say; 'Wa 'Alaika (and upon you)
Reference: Bukhari 6928