Major and Minor Sins
In Islam, a sin is any act a person chooses to take in defiance of God's law and order. Islam classifies sins according to the severity of their consequences on individuals and society, with the harshest of warnings reserved for those actions that have the potential of harming the community as a whole. Other acts are personal in nature and are therefore considered to be more minor.
A major sin in Islam is one that is directly warned against in the Qur'an, with reference to a specific punishment in this life or the Hereafter. These actions are considered more severe, as they have disastrous consequences on individuals and societies. Among the major sins are such acts as murder, theft, perjury, bribery, slander, adultery, drinking alcohol, and fighting unjustly between people. They also include violations against God, such as polytheism or neglect of religious duties.
One may also make minor violations; these have not been given a specific punishment in the Qur'an. That is not to say such actions are insignificant; rather, their effect is on a smaller scale than those mentioned previously. Examples of minor sins in Islam include bragging, flirting, lying, and swearing. These actions, taken individually, do not constitute a breakdown in society or a severe violation of others' rights. However, they are personality faults and if one persists in such behavior, it could rise to a higher level.
The Qur'an describes a people whose “hearts have been sealed by the sins they have accumulated” (Qur'an 83:14). The Prophet Muhammad explained this verse by saying that when a person sins even once, it is like a black dot is placed on his heart. When he sincerely repents, the dot is erased. However, if he persists and continues in the sin, the dot will expand until it covers his entire heart. When this happens, the person ceases to recognize the difference between good and evil. Therefore it was the Prophet Muhammad's advice to seek forgiveness from God for every mistake and counter it with increased worship and good deeds.
In Islam, almost all sins can be forgiven by God if one truly repents and vows not to repeat the same mistake. Repentance is known as tauba in Arabic, which means “to turn back.” In order to repent, one must recognize the sin and give it up, and one must feel a sense of remorse for the act. Then one resolves never to make the same mistake again. If the action has caused harm to any other person, one must attempt to make amends by compensating them (if possible) or seeking their forgiveness.
The overall message of the Qur'an is one of God's Mercy and Forgiveness. The One Who created us knows our weaknesses, and Muslims believe that God forgives all sins. The Qur'an confirms this over and over again: “Oh My servants who have wronged against their souls: do not despair of God's Mercy! God forgives all sins; for He is indeed Forgiving, Compassionate” (Qur'an 39:53).