Sin in Islam is an important term in Islamic ethics. Muslims see sin as a violation of God’s will or commands the deliberate misuse of the freedom that has been given to human beings.
The Quran describes these sins throughout the text and demonstrates that some sins are more punishable than others. A clear distinction is made between major and minor sins (Quran 53:31-32)
Among the most serious offenses is idolatry, associating other gods, or anything else, with the one true God.
Islam rejects the doctrine of original sin. In which it is mentioned in the Quran:
“And no bearer of burdens will bear the burden of another. And if a heavily laden soul calls [another] to [carry some of] its load, nothing of it will be carried, even if he should be a close relative. You can only warn those who fear their Lord unseen and have established prayer. And whoever purifies himself only purifies himself for [the benefit of] his soul. And to Allah is the [final] destination”.(Quran 35:28)
If sin is a violation of God’s commands, departing from the straight path of Islam, to repent is to turn toward God, literally to return (tawbah) to God, who is compassionate and forgiving, after falling into sin or error.
Repentance is a major theme, mentioned over seventy times in the Quran, and the title of an entire chapter (Surah 9).
Repentance in Islam is a personal, moral, individual act of remorse. It is an informal act that does not require a formal act of confession or atonement, as in some forms of Christianity.
In cases where the sin has violated the rights of others, restitution is required. If the sin does not infringe on other's’ rights but involves an offense against God, then penitence, remorse, and making a resolution to abstain from the sin in the future are sufficient.
In Islam, all sins can be forgiven except associating others with God and dies in that state . Whatever sins a Muslim commit, will be pardoned if he offers sincere repentance and does a lot of good deeds. The good deeds wipe out the bad ones. The door of repentance is always open and Allah will accept the repentance until the Muslim dies.