The Prophet ﷺ said: "Allah, the Almighty, said: 'Every deed of the son of Adam is for him, except for fasting; it is for Me, and I shall reward for it." [Agreed upon]

This means:

● Every deed of the son of Adam may be affected by showing off (riyaa’), except fasting, because only Allah knows whether a person is truly fasting or not.

● The reward for all deeds is known—one good deed is multiplied tenfold—except fasting, as only Allah knows its true reward.