Bani Israil 17:55 وربك اعلم بمن في السماوات والارض ولقد فضلنا بعض النبيين على بعض واتينا داوود زبورا ٥٥

رَّبُّكُمْ أَعْلَمُ بِكُمْ

(Your Lord knows you best;) O mankind, meaning, He knows best who among you deserves to be guided and who does not deserve to be guided.

إِن يَشَأْ يَرْحَمْكُمْ

(if He wills, He will have mercy on you,) by helping you to obey Him and turn to Him.

أَوْ إِن يَشَأْ يُعَذِّبْكُمْ