Do major sins—from which a servant has sincerely repented—nullify the reward of righteous deeds that preceded them, and does the reward of those good deeds return to him after his repentance?

If a person repents sincerely from major sins, Allah accepts their repentance, and they become as if they had never sinned, according to the Prophet's (peace be upon him) saying: "The one who repents from sin is like one who has no sin." All the acts of obedience they performed before their sin are also restored to them. The understanding of the verse: "And whoever of you reverts from his religion and dies while he is a disbeliever - for those, their deeds have become worthless in this world and the Hereafter" indicates that if someone apostatizes and then returns to Islam, their deeds performed before their apostasy are restored to them. Similarly, for one who repents from sins, their previous deeds are restored to them. Their sins do not nullify their acts of obedience as long as they have repented from them, and the reward for their acts of obedience remains for them.