(4) باب النَّهْىِ عَنِ ابْتِدَاءِ، أَهْلِ الْكِتَابِ بِالسَّلاَمِ وَكَيْفَ يَرُدُّ عَلَيْهِمْ
'A'isha reported that some Jews came to Allah's Apostle (ﷺ) 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 (ﷺ) 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).
Reference: Sahih Muslim 2165 c
In-book reference: Book 39, Hadith 13
USC-MSA web (English) reference(deprecated numbering scheme): Book 26, Hadith 5386