An-Nisa 4:40

Inna Allaha la yathlimumithqala tharratin wa-in taku hasanatan yudaAAifhawayu/ti min ladunhu ajran AAatheema

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.

Surely, Allah does not wrong (anyone), even to the measure of a particle. If it is a good deed, He multiplies it, and gives a great reward out of His Own pleasure.