On this issue, we would like to quote Sheikh Ahmad Kutty, an Islamic scholar who states:
Since Allah’s laws are solely intended to save humanity from the destructive nature of the evil inclinations inherent in our souls, He has declared certain acts as enormous sins because of their extremely disastrous consequences and effects on individuals and societies. The greater the consequences, the greater their enormity and gravity. Allah teaches us in the Qur’an that the previous nations were destroyed due to their persistence in sins and their failure to heed the call of the Messengers to repent and amend their ways.
We are also told in no unmistakable terms that we stand to gain happiness and prosperity in both worlds by shunning sins altogether and following the right way.
Thus sins are termed as major or minor essentially because of their gravity or enormity in terms of their consequences or effects on individuals and society. Accordingly, some sins are considered most heinous, abominable; they incur divine wrath or punishment or curse or serious consequences. Among the most obvious examples of such sins are: shirk (associating partners with Allah), displeasing one’s parents, murder, bearing false testimony, adultery or fornication, practicing black magic, devouring riba (interest), devouring an orphan’s wealth, robbing others, etc.
The minor sins, on the other hand, are those which do not fall in the above category. They are minor in so far as they do not incur any of the above serious consequences.
All major sins require tawbah or sincere repentance. Sincere repentance involves four steps: The first is for a person to be deeply remorseful of the sin; secondly, to refrain from it and all of the circumstances that led to it; thirdly, to make a firm resolution never to do it again; and finally, to follow it up by whatever good deeds one can possibly do. Allah says, “Verily good deeds wipe out bad deeds.” (Hud: 114). The Prophet (peace and blessings be upon him) further explains this by saying: “Allah does not wipe out bad deeds through bad deeds; rather He blots them out through good deeds.”
As for the minor sins such as flirting or hugging, or touching a member of the opposite sex, et cetera, if they are not habitual actions, they are considered minor sins, and they can be wiped out by repentance, istighfar (asking Allah for forgiveness) and good works. Once a person came to the Prophet (peace and blessings be upon him) and presented himself saying, “I happened to see a woman on my way and got everything from her except sexual intercourse.” The Prophet told him that he had been forgiven because of his prayer with him (with sincere feeling of repentance and remorse). The lesson to learn from this story is that such sins may be forgiven by good works followed by feelings of remorse and penitence.
Having said this, however, we must remember the important point stated by Imam Ghazali: Persistence in minor sins will turn them into major ones. Thus a person who is committing such acts and persisting in them is guilty of major sins as opposed to someone who is guilty of occasional lapses. Therefore, the only way to repent in such case is to quit such habits cold turkey and also cut oneself off totally and entirely from all associations or circumstances that led him to such sins. He/she cannot hope to change for the better without such serious measures.
If, instead, one were to persist in them, he/she would end up losing the purity of heart, the moral conscience. The Prophet (peace and blessings be upon him) warned us against the pervasive effects of sins on our souls. He said that when a person commits a sin, it falls like a black dot on the clean slate of his heart. If he repents, the dot is erased. If, however, he persists in the same and continues to sin, the dot will continue to expand until it covers his entire heart, in which case his spiritual soul becomes completely sealed off. As a result he fails to recognize good as good and evil as evil. The Prophet said this is what Allah has repeatedly warned us against in the Qur’an: “Nay, their hearts have been sealed by the sins they have accumulated.” (Al-Mutaffifeen: 14).
To conclude: We must always exercise extreme vigilance and caution against all types of sins, both major and minor. We must develop the habit of repenting in the prescribed manner and expiate for our sins by consistently engaging in good works as best as we can. May Allah help us all to protect the purity of our hearts, and may He grant us forgiveness and mercy. Ameen.