What is the expiation for missed acts of worship, and how can one continue in obedience to avoid returning to disobedience?

If you repent with sincere and true repentance, Allah will forgive your sins no matter how great they are, for His mercy encompasses all things, and a sincere penitent is like one who has not sinned. Allah has promised forgiveness to those who repent, as He states: (Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful") [Az-Zumar: 53], and His saying: (And He is the One who accepts repentance from His servants and pardons sins) [Ash-Shura: 25]. Your remorse is evidence of the sincerity of your repentance, and remorse is repentance, and the one who repents from sin is like one who has no sin.

To make up for missed obligatory acts of worship: - For Zakat: Refer to Fatwa No.: 139941. - For missed prayers: Refer to Fatwas No.: 55179 and No.: 66593. - For missed Ramadan fasting: Refer to Fatwa No.: 98230. You can compensate for what you missed of supererogatory acts of worship by striving hard in them.