The Book of Greetings
Ṣaḥīḥ Muslim 5654
سَلَّمُوا عَلَيْكُمْ يَقُولُ أَحَدُهُمُ السَّامُ عَلَيْكُمْ فَقُلْ عَلَيْكَ
sallamūā ʿalaykum yaqūlu aḥaduhumu as-sāmu ʿalaykum faqul ʿalayka
Transliteration generated from the Arabic vowel marks
The full narration
Ibn 'Umar reported Allah's Messenger (ﷺ) as saying:When the Jews offer you salutations, some of them say as-Sam-u-'Alaikum (death be upon you). You should say (in response to it): Let it be upon you
Source
Ṣaḥīḥ Muslim · 5654
Ṣaḥīḥ
- Agreed upon as authentic (al-Bukhārī / Muslim)