{Have you not seen those who were forbidden from private conversation} - They are the Jews who were forbidden from conversing privately regarding disobedience to Allah, disobedience to the Messenger, and casting aspersions upon the religion of Allah. {Then they return to that which they were forbidden from} - They would seclude themselves with one another. {And they converse privately about sin and aggression} (Folio 355). Sin: disobedience; aggression: injustice. {And when they come to you, they greet you with a greeting that Allah does not greet you with} - They would greet the Prophet and his companions, saying: "As-Samu 'alaykum" (Death be upon you), and "as-sam" means death, according to some of them. He said: So the Messenger of Allah would respond to them in kind; then Gabriel came to him and informed him that they were not saying that as a form of greeting. Consequently, the Messenger of Allah (peace and blessings of Allah be upon him) said to his companions: "If one of the People of the Scripture greets you, then say: 'Wa 'alayk' (And upon you)." That is: upon you.
﴿أَلَمْ تَرَ إِلَى الَّذِينَ نُهُوا عَن النَّجْوَى﴾ هم الْيَهُود نُهُوا أَن يتناجوا بِمَعْصِيَة الله ومعصية الرَّسُول، والطعن فِي دين اللَّه ﴿ثُمَّ يعودون لما نهوا عَنهُ﴾ كَانُوا يخلون بَعضهم بِبَعْض ﴿ويتناجون بالإثم والعدوان﴾ (ل ٣٥٥) الْإِثْم: الْمعْصِيَة، والعدوان: الظُّلم ﴿وَإِذَا جَاءُوكَ حَيَّوْكَ بِمَا لَمْ يُحَيِّكَ بِهِ اللَّهُ﴾ كَانُوا يسلمُونَ على النَّبِي وَأَصْحَابه فَيَقُولُونَ: السَّام عَلَيْكُم، والسَّامُ: الْمَوْت فِي قَول بَعضهم قَالَ: فَكَانَ رَسُول الله يرد عَلَيْهِم على حد السَّلَمِ؛ فَأَتَاهُ جِبْرِيل فَأخْبرهُ أَنهم لَيْسُوا يَقُولُونَ ذَلِك على وَجه التَّحِيَّة فَقَالَ رَسُول الله ﷺ لأَصْحَابه: " إِذا سلم عَلَيْكُم من أهل الْكتاب فَقولُوا: عَلَيْك ". أَي: عَلَيْك
