وَعَنْهُ أَيْضًا أَنَّ يَهُودِيًّا أَتَى النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ وَهُوَ مَعَ أَصْحَابِهِ فَقَالَ السَّامُ عَلَيْكُمْ فَرَدَّ عَلَيْهِ الْقَوْمُ فَقَالَ نَبِيُّ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قُلْتَ كَذَا وَكَذَا قَالَ نَعَمْ فَقَالَ نَبِيُّ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِذَا سَلَّمَ عَلَيْكُمْ أَحَدٌ مِنْ أَهْلِ الْكِتَابِ فَقُولُوا عَلَيْكَ أَيْ عَلَيْكَ مَا قُلْتَ
Narrated from Sayyiduna Anas (may Allah be pleased with him) that a Jew came to the Noble Prophet (peace and blessings be upon him) while he was sitting with his companions, and he said: "As-Saam Alaikum (death be upon you)." The people replied to him, but the Messenger of Allah (peace and blessings be upon him) said to him: "Did you say such and such?" He said: "Yes." Then the Prophet (peace and blessings be upon him) said: "When any of the People of the Book greet you, then you should only say 'Alaika (upon you).' That is, whatever you said, the same be upon you."