[Machine] I heard Anas say that a man from the people of the Book came and greeted the Prophet ﷺ . He said "As-Salamu Alaykum" (peace be upon you), and Umar said, "O Messenger of Allah, should I not strike his neck?" The Prophet ﷺ said, "No, if they greet you with peace, then say 'wa 'alaykum" (and peace be upon you too).  

سَمِعْتُ أَنَسًا يَقُولُ جَاءَ رَجُلٌ مِنْ أَهْلِ الْكِتَابِ فَسَلَّمَ عَلَى النَّبِيِّ ﷺ فَقَالَ السَّامُ عَلَيْكُمْ فَقَالَ عُمَرُ يَا رَسُولَ اللهِ أَلَا أَضْرِبُ عُنُقَهُ؟ قَالَ لَا إِذَا سَلَّمُوا عَلَيْكُمْ فَقُولُوا وَعَلَيْكُمْ  

[Machine] A Jewish man passed by the Messenger of Allah ﷺ and said, "Assalamu alaikum," (peace be upon you). The Messenger of Allah ﷺ replied, "Wa alaikum assalam. Do you know what he said?" They said, "He said, 'Assalamu alaikum' to you," The Messenger of Allah ﷺ said, "Should we not kill him?" They replied, "No, but when the people of the book greet you with 'Assalamu alaikum,' you should reply with 'Wa alaikum assalam.'"  

أَنَّ يَهُودِيًّا مَرَّ عَلَى رَسُولِ اللهِ ﷺفَقَالَ السَّامُ عَلَيْكَ فَقَالَ رَسُولُ اللهِ ﷺ وَعَلَيْكَ أَتَدْرُونَ مَا قَالَ؟ قَالَ السَّامُ عَلَيْكُمْ فَقَالُوا أَلَا نَقْتُلُهُ فَقَالَ لَا وَلَكِنْ إِذَا سَلَّمَ عَلَيْكُمْ أَهْلُ الْكِتَابِ فَقُولُوا وَعَلَيْكُمْ  

[Machine] "A Jew greeted the Prophet ﷺ and his companions, saying, 'As-salamu 'alaykum' (peace be upon you). The Prophet ﷺ asked, 'Do you know what he said?' They replied, 'Yes, he greeted us by saying 'as-salamu 'alaykum.' The Prophet ﷺ said, 'No, he actually said 'as-samu 'alaykum' (death be upon you), meaning that you should abandon your religion. So when a person from the People of the Book greets you, respond by saying 'wa 'alayk' (and upon you).'"  

أَنَّ يَهُودِيًّا سَلَّمَ عَلَى النَّبِيِّ ﷺ وَأَصْحَابِهِ فقَالَ السَّامُ عَلَيْكُمْ فقَالَ النَّبِيُّ ﷺ «أَتَدْرُونَ مَا قَالَ؟ » قَالُوا نَعَمْ سَلَّمَ عَلَيْنَا قَالَ «لَا إِنَّمَا قَالَ السَّامُ عَلَيْكُمْ أَيْ تُسَامُونَ دِينَكُمْ فَإِذَا سَلَّمَ عَلَيْكُمْ رَجُلٌ مِنْ أَهْلِ الْكِتَابِ فَقُولُوا وَعَلَيْكَ»  

Messenger of Allah ﷺ said, "When the Jews greet you, they usually say, 'As-Samu 'alaikum (Death be on you),' so you should say (in reply to them), 'Wa'alaikum (And on you). (Using translation from Bukhārī 6257)   

"إِنَّ اليهُودَ إِذَا سَلَّمَ علَيْكُمْ أحدُهُم فَإِنَّمَا يقُولُ: السَّامُ علَيْكُم، فقولوا: وعلَيْكُم ".