Hadith 227

If one of the People of the Scripture (i.e. Christians and Jews) greets you, saying As-Salāmu `alaykum, then say (to him): Wa `alaykum. If one of the People of the Scripture (i.e. Christians and Jews) greets you saying As-Salaamu `alaykum, then say (to him): And upon you . Reference: Al-Bukhari, cf. Al-Asqalani, Fathul-Bari 11/42, Muslim 4/1705.