فَمَنْ يَعْمَلْ مِثْقَالَ ذَرَّةٍ خَيْرًا يَرَهُ
Whoever does an atom's weight of good will see it. (Al-Zalzalah 99:7)
Mithqāla dharrah indicates an exceedingly small amount. A good deed is not to be dismissed simply because it appears minor. Even the smallest good is not lost in Allah's reckoning and has its recompense.