of Allah (saas) said: "Every deed of the son of Adam will be multiplied for him, between ten and seven hundred times for each merit. Allah said: 'Except for fasting, for it is for Me and I shall reward for it.'" (sahih)
قَالَ رَسُولُ اللَّهِ ﷺ كُلُّ عَمَلِ ابْنِ آدَمَ يُضَاعَفُ لَهُ الْحَسَنَةُ بِعَشْرِ أَمْثَالِهَا إِلَى سَبْعِمِائَةِ ضِعْفٍ قَالَ اللَّهُ سُبْحَانَهُ إِلاَّ الصَّوْمَ فَإِنَّهُ لِي وَأَنَا أَجْزِي بِهِ