Homicide
Another which is very indecent and reproachable in the holy religion of Islam is homicide and killing an innocent person.
Homicide is one of the mortal sins. In His words, the Almighty Allah equals the killing of a human being with massacre of all the human beings. This is because the killer of one person deals with humanity and humanity is the same in one person or in one thousand persons.

Infringing Upon The Property of Orphans
Just as benevolence towards people is logically and religiously praiseworthy, malevolence towards Allah's servants is unfair and blameworthy. Injustice and oppression are strongly prohibited by the holy religion of Islam in several instances, one of which is the infringement upon the property of orphans.
Misappropriating the property or money of an orphan is one of the mortal sins in Islam. It is specified in the Holy Qur'an that whoever misappropriates an orphan's property eats fire indeed and will soon be thrown in the blazing fire of hell. According to the statements of the infallible Imams (as), the main reason for so much emphasis is that if an aged man (who is not an orphan) is oppressed, he may defend his rights, but an orphan is unable to do so.

Disappointment for The Blessings of Allah
In Islam, one of the most dangerous sins is being disappointed for Allah's blessings.
The Almighty Allah states: "Say: O my servants! who have acted extravagantly against their own souls, do not despair of the mercy of Allah; surely Allah forgives the faults altogether. surely He is the Forgiving, the Merciful (39:53)."
At another place, the person who despairs of the blessings of Allah is considered to be an unbeliever. The reason behind this is that if a person despairs of the blessings and forgiveness of Allah, he will no longer have any internal stimulant to perform good and praiseworthy deeds in his life and to refrain from committing dhanb kabir (mortal sin) and dhanb saghir (venial sin) and indecent actions, because the main motivation for the two items mentioned above is "hope for Allah's blessings" and "deliverance from the punishment of Allah". This expectation does not exist in such a person. There is no difference between this person and the one who does not believe in any religion as far as mental and internal qualities are concerned.

Anger and Wrath
Anger is a condition that prompts man to take revenge and he gets internal satisfaction in taking revenge. If a man acts with laxity in controlling himself, his commonsense will be immediately subdued by anger and wrath and every indecent and unfair action will seem right to him to the point that he becomes more rapacious than any beast.
Strict orders have been issued by Islam for preventing the outburst of anger and severe reproachment has been set against following it. The Almighty Allah has shown great favors towards those who control their anger and remain patient when they are angry.
As the Almighty Allah states: "...And those who restrain (their) anger and pardon men...(3:134)."
In regard to the characteristics of believers, the Almighty Allah states: "... And whenever they are angry they forgive (42:37)."

Bribery
Receiving money or a gift in return for a judgment or for the accomplishment of a task which is the duty of the receiver is called bribery.
Bribery is a mortal sin in Islam. The person who commits this sin is deprived of many social privileges of religion (justice) and deserves Allah's punishment. This matter has been specified in the Holy Book and the ahadith.
The Holy Prophet (S) has cursed tile givers, receivers, and the mediators of bribe.
The sixth infallible Imam (as) also states: "Receiving bribe for administering justice equals blasphemy to Allah".
Surely, all these reproachments apply to the bribe taken for the judgment of truth or for administering justice. The sin of the bribe taken for the judgment contrary to truth and for unjust deeds is far greater and its retribution is much severer.

Theft
Theft is an unfair and indecent action that threatens the financial security of the society. It is self-evident that the fundamental source of human life is the property and wealth which man acquires at the expense of his life. Man protects h is wealth so that it can be safeguarded against any infringement by others so that it can consequently remain as the protection and backing of the society.
Surely, breaking through this protection and disrupting this order mean ruining man's life which has been spent to acquire such wealth. It results in disabling men to perform most of their activities and renders them inefficient.
That is why, in regard to the punishment of this repugnant action which is considered to be perfidious by the thief's self-conscience as well, Islam has ordered to cut the thief's hand (four fingers from the right hand). The Almighty Allah states: "And (as for) the man who steals and the woman who steals, cut off their hands as a punishment for what they have earned. (5:38)."

Selling Underweight
In Islam, selling underweight is a mortal sin. In His words, the Almighty Allah reproaches and threatens those who commit it and states: "Woe to the defrauders....Do not these think that they shall be raised again, for a mighty day (83:1, 4, 5)."
Besides doing injustice to the people and stealing their money by way of theft, a person who sells underweight causes people to lose their confidence in him and gradually loses his customers and at last his own money.

The General Penalty of Sins in Islam
These indecent deeds are called mortal sins in Islam and the Almighty Allah has clearly promised to punish those who commit these sins.
In addition to establishing severe punishments for some of these sins, Allah has excluded those who commit these sins (even once) from the just, i.e., He has taken away from them the honor of being a righteous member of the human society.
Whoever commits a mortal sin loses his justice and gets deprived of the privileges that a righteous member of the society can enjoy. He cannot be in charge of one of the various positions of the Islamic government; for example, he cannot become khalifah or imam al-jama'ah (the imam of congregational salat). His testimony to the benefit or detriment of others is not acceptable. He will remain in this state until he repents and develops the quality of justice in himself once again by constantly having taqwa (piety).