Quran

The (treacherous) is one who betrays repeatedly, and the (sinful) is one who betrays intentionally. Thus, the one who committed treachery once, as well as other acts of treachery that occurred unintentionally or heedlessly are excluded from this definition. Ibn Atiyah: 2/110.
Question: When is a person described as (treacherous)? When is he described as (sinful)?

(Those who betray themselves), they wrong themselves by committing sins. (Indeed, Allah does not like the treacherous and sinful), a frequent traitor who betrays excessively. Abu Hayyan (a prominent interpreter) said: "The exaggerated form of the Arabic word (treacherous) is used in order to exclude one who committed treachery once, and one who did it unintentionally or heedlessly." Al-Alusi: 5/141.
Question: The exaggerated form of Arabic word (treacherous) is used. Why?

The betrayal of others is described as betrayal of themselves because its evil consequences and harm will return to them. Al-Alusi: 5/140.
Question: Why was their betrayal of others described as a betrayal of oneself?

Ali bin Abi Talib (t) said: Abu Bakr (t) told me -and Abu Bakr spoke the truth- he said: I heard the Messenger of Allah (r) saying: " There is no servant who commits a sin, then performs ablution, prays two rak’ahs, and seeks Allah's forgiveness, except that he will be forgiven." Then he recited this verse: (Whoever commits evil or wrongs himself, then seeks Allah's forgiveness will find Allah All-Forgiving, Most Merciful)." Al-Qurtubi: 7/117.
Question: There are many expiations for sins. Give one example?

It is called wronging oneself because the person's nafs (self) is not his property, such that he may dispose of it as he wishes; rather it is the property of Allah Who has made it a trust with which He has entrusted His servant and enjoined him to keep it (his nafs) on the straight path in word and deed. So, he should strive to teach himself as he has been enjoined and strive to do what is required. Striving to follow any other path is wronging himself, betraying himself, and diverging himself from justice and fairness. Al-Saadi: 201.
Question: Why are sins called wronging oneself?

If evil deeds become prevalent and no one objects to them, then the punishment will become widespread and the burden of sin will encompass everyone. That does not contradict the rulings of this verse because whoever abandons the obligatory denunciation has earned a bad deed. Al-Saadi: 201.
Question: When does the punishment of evil affect the perpetrator, and when does it affect society?

(And Allah is All-Knowing, Most Wise) by His knowledge and wisdom, He knows about the sin and what results from it, what prompted it and the punishment that is due for it. He knows the state of the sinner and that if he commits the sin because of the evil inclination of his soul, even though most of the time he is obedient to Allah, He will forgive him and enable him to repent. But if he committed it due to his daring to commit forbidden acts, showing contempt for his Lord and taking His punishment lightly, then this is far from forgiveness and far from success in repentance. Al-Saadi: 201.
Question: What are the two types of sinners?