2163.01
Anas b. Malik reported Allah's Messenger (ﷺ) as saying:When the People of the Book offer you salutations, you should say: The same to you
Sahih MuslimHadith 2163 (2 narrations)
2163.02
Anas reported that the Companions of Allah's Apostle (ﷺ) said to him:The People. of the Book offer us salutations (by saying as-Salamu- 'Alaikum). How should we reciprocate them? Thereupon he said: Say: Wa 'Alaikum (and upon you too)