(Thwaha) 20 : 47
فَأْتِيَاهُ فَقُولَا إِنَّا رَسُولَا رَبِّكَ فَأَرْسِلْ مَعَنَا بَنِي إِسْرَائِيلَ وَلَا تُعَذِّبْهُمْ ۖ قَدْ جِئْنَاكَ بِآيَةٍ مِنْ رَبِّكَ ۖ وَالسَّلَامُ عَلَىٰ مَنِ اتَّبَعَ الْهُدَىٰ

So they both came to him and said: “Indeed we are Messengers of your Lord; so you send with us the Children of Israel and you don’t punish them, We have come to you with a Sign from your Lord, and peace will be upon he who follows the Guidance”.

Only the one who follows the Guidance Adhikr will prosper. So believers will only greet with peace upon the one who follows Adhikr as explained in verse 4: 86. See explanation 6: 54 and 17: 102.