Surah An-Nisa, Verse 40

إِنَّ ٱللَّهَ لَا يَظۡلِمُ مِثۡقَالَ ذَرَّةٖۖ وَإِن تَكُ حَسَنَةٗ يُضَٰعِفۡهَا وَيُؤۡتِ مِن لَّدُنۡهُ أَجۡرًا عَظِيمٗا٤٠

inna l-laha lā yaẓlimu mith'qāla dharratin wa-in taku ḥasanatan yuḍāʿif'hā wayu'ti min ladun'hu ajran ʿaẓīman

Indeed, Allāh does not do injustice, [even] as much as an atom's weight; while if there is a good deed, He multiplies it and gives from Himself a great reward.