Qur'an 4:40

إِنَّ ٱللَّهَ لَا يَظْلِمُ مِثْقَالَ ذَرَّةٍ ۖ وَإِن تَكُ حَسَنَةً يُضَـٰعِفْهَا وَيُؤْتِ مِن لَّدُنْهُ أَجْرًا عَظِيمًا

“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.”

An-Nisaa 4:40 · Saheeh International