Major sins are those acts which will be replaced with great deal of punishment not only in this world, but in hereafter as well. Below are given few of major sin;
Shirk or ascribing partners with ALLAH is that sin which will never be pardoned because when a person commits shirk, he associates partners with ALLAH and goes beyond the concept of oneness of ALLAH. With the passage of time, humanity lost itself into the matters of worldly affairs and forgot the message of ALLAH and who their GOD was. Shirk comes with suspicions. When a person is suspicious that something might not hurt him or cause him any other damage he starts to seek ways to get rid of it, by sometimes praying it and sometimes praying others against it. This shows the weakness of iman.
4:48. Verily, Allah forgives not that partners should be set up with him in worship, but He forgives except that (anything else) to whom He pleases, and whoever sets up partners with Allah in worship, he has indeed invented a tremendous sin.
2: to not call kafir, a kafir
It is another big sin to call a kafir a Muslim or a right person. A kafir is one who does not believe in ALLAH. Thus a kafir is not be made friend nor he should be taken as kin. In Quran, ALLAH swt even told us to disown even the parents who are kafirs because living with a kafir wil weakens the iman of a Muslim. But this must not be confused with dawah. To do dawah means to invite others towards Islam. But making friends with kafirs or taking them as relatives’ means that you do not care for the honor of ALLAH and thus you commit a grave sin.
3: blasphemy
Though blasphemy is not even considered as a minor sin today, but it is a major sin., and those who made fun of Muhammad s.a.w.w in the life time of Muhammad s.a.w.w and even after Him, most of them were killed for this. To love and respect Muhammad s.a.w.w is the most important thing for every Muslim to do. If we cannot listen a bad word about our own parents, how could we make our ears listen to the filth against our beloved Prophet Muhammad s.a.w.w?
4: renouncing Islam
Apostasy is another major sin and in most cases apostates are killed no matter if one comes up with thousands of explanations. It is written in Quran and explained from sahih hadith that those apostates who renounce Islam for the sake of some rewards or to defame Islam, they should be killed. These people become a danger for the imans of even other people and sometimes we see them given protection by non Muslims and their filthy works are rewarded by them. Slamn rushdi, taslima nasrin and some others are the prominent apostates who instead of clearing their misconceptions relied on their personal opinions about Islam and they are still under protection of non Muslims.
5: innovation
To innovate new things in Islam and to reject few things from Islam and hadith as well as from Quran is another major sin. The innovators are the people who change the shariat according to their damned wishes and while doing so, they do not understand for a second that they have not only ruined their own imans but they have ruined their follower’s iman as well. Today we see many innovators misleading people and people too follow them blindly.
6: rejection of hadith
Rejection of sunnah and only believing in Quran is also a major sin. Muhammad s.a.w.w predicted about such people who will reject hadith. Also, it is against the orders of ALLAH to obey Him and to obey His Messenger s.a.w.w. such people are excluded from the folds of Islam.
7: murder
Murder is a grave sin which is condemned in Islam is very clear words. Quran says that one who kills an innocent has killed a whole humanity. Thus Quran condemns it and does not restricts unjust killing to Muslim but also to non Muslims. Such a person is punished in this world and he will be on the mercy of ALLAH In this matter in the hereafter too.
8: suspicions
Suspicions are the human perceptions about the things he sees. These perceptions made him sometimes to disbelief and sometimes to harm other. Thus false perceptions and suspicions without any reason are restricted in Islam. They have no ground in Islam and they are always baseless.
9: lies and back biting
Lies and backbiting also come under major sins. Lies can never be hidden and backbiting is as if somebody eats his dead brother’s meat which is degusting. When a person lies he cuts his good deeds and when a person backbites, he gives a part of his good deeds to the person about whom he backbite and takes his sins as reward. Backbiting is to tell a truth (a negative thing) about a person in his absence.
10: jadu-magic
Magic is a grave sin and it comes under shirk. Magic is a knowledge which is to invoke evil jins and devils for fulfilling a purpose. The magician might not even know that he is committing a sin, but he actually calls upon jins instead of Allah and that too to harm other. Magic was never used for good from the day first. It was always taken as an easy source to sow the seed of hatred between people thus magic is not only a shirk but also a sin of discomforting others because of one’s evil desires.