حَيَّ

وَإِذَا حُيِّيتُم بِتَحِيَّةٍۢ فَحَيُّوا۟ بِأَحْسَنَ مِنْهَآ أَوْ رُدُّوهَآ ۗ إِنَّ ٱللَّهَ كَانَ عَلَىٰ كُلِّ شَىْءٍ حَسِيبًا

And when you are greeted with a greeting, greet [in return] with one better than it or [at least] return it [in a like manner]. Indeed Allāh is ever, over all things, an Accountant.

أَلَمْ تَرَ إِلَى ٱلَّذِينَ نُهُوا۟ عَنِ ٱلنَّجْوَىٰ ثُمَّ يَعُودُونَ لِمَا نُهُوا۟ عَنْهُ وَيَتَنَـٰجَوْنَ بِٱلْإِثْمِ وَٱلْعُدْوَٰنِ وَمَعْصِيَتِ ٱلرَّسُولِ وَإِذَا جَآءُوكَ حَيَّوْكَ بِمَا لَمْ يُحَيِّكَ بِهِ ٱللَّهُ وَيَقُولُونَ فِىٓ أَنفُسِهِمْ لَوْلَا يُعَذِّبُنَا ٱللَّهُ بِمَا نَقُولُ ۚ حَسْبُهُمْ جَهَنَّمُ يَصْلَوْنَهَا ۖ فَبِئْسَ ٱلْمَصِيرُ

Have you not considered those who were forbidden from private conversation [i.e., ridicule and conspiracy] and then return to that which they were forbidden and converse among themselves about sin and aggression and disobedience to the Messenger? And when they come to you, they greet you with that [word] by which Allāh does not greet you and say among themselves, "Why does Allāh not punish us for what we say?" Sufficient for them is Hell, which they will [enter to] burn, and wretched is the destination.