According to rahyafte (the missionaries and converts website):So it is not illogical to divide sins into small and big sins.
Imam Sadiq (AS) has enumerated the big sins mentioned in the Quran as the following:
1- The biggest Kabira (major sin) is Shirk (polytheism), as the Quran says: “God will deprive anyone who considers anything equal to God of Paradise and his dwelling will be fire.” (Verse 72 of Surah Al-Ma’idah)
2- Losing hope in God’s mercy
God says in Verse 87 of Surah Yusuf: “… do not despair of receiving comfort from God; only the unbelievers despair of receiving comfort from Him.”
3- Feeling secure from the retribution of God
“Did they consider themselves secure from the retribution of God- ? No one can have such attitude except those who are lost.” (Verse 99 of Surah Al-A’raf)
4- Disrespecting parents
The Quran says in Verse 32 of Surah Maryam: “(Jesus said): He has commanded me to be good to my parents and has not made me an arrogant rebellious person.”
5- Killing innocent people:
“The punishment for one who purposely slays a believer will be to live in hell fire forever. God is angry with him and has condemned him. He has prepared for him a great torment.” (Verse 93 of Surah An-Nisa)
6- Defaming chaste women
“Surely those who accuse chaste believing women, unaware (of the evil), are cursed in this world and the hereafter, and they shall have a grievous chastisement.” (Verse 23 of Surah An-Nur)
7- Consuming the properties of orphans
“Those who wrongfully consume the property of orphans are, in fact, consuming fire in their bellies and they will suffer the blazing fire.” (Verse 10 of Surah An-Nisa)
8- Running away from war front
“If anyone on that day turns his back to them in flight, except when maneuvering to fight, or to join another party, he shall be laden with the Anger of Allah and Gehenna (Hell) shall be his refuge an evil arrival.” (Verse 16 of Surah Al-Anfal)
9- Usury
“Those who consume usury shall not rise up (from their tomb) except as he who rises in madness that Satan has touched.” (Verse 275 of Surah Al-Baqarah)
10- Sorcery and witchcraft
“They knew very well that one who engaged in witchcraft would have no reward in the life hereafter.” (Verse 102 of Surah Al-Baqarah)
11- Fornication
“… who do not worship idols besides God, nor without a just cause murder a soul to whom God has granted amnesty, who do not commit fornication, for those who do so have committed a sin and on the Day of Judgment their torment will be double. They will suffer forever in disgrace.” (Verses 68-69 of Surah Furqan)
12- Taking false oath
“Those who sell the promise of Allah and their own oaths for a little price shall have no share in the Everlasting Life. Allah will neither speak to them, nor look at them, nor purify them on the Day of Resurrection. Theirs shall be a painful punishment.” (Verse 77 of Surah Al Imran)
13- Defrauding
“It is not for a Prophet to defraud, whosoever defrauds shall bring that fraud on the Day of Resurrection.” (Verse 161 of Surah Al Imran)
14- Not paying Zakat
“On that Day they (the treasures) will be heated in the fire of Gehenna (Hell), and their foreheads, sides, and backs will be branded with them, and told: ‘These are the things which you have treasured. Taste then that which you were treasuring!’” (Verse 35 of Surah At-Tawbah)
15- Concealing testimony
“He who conceals it, his heart is sinful. Allah has knowledge of what you do.” (Verse 283 of Surah Al-Baqarah)
16- Drinking wine
“Believers, wine and gambling, idols and divining arrows are abominations from the work of satan. Avoid them, in order that you prosper.” (Verse 90 of Surah Al-Ma’idah)
17- Abandoning Salah and other obligatory acts intentionally
18 and 19- Breaking promises and severing family ties
“Those who disregard their covenant with God after He has taken such a pledge from them, who sever the proper relations that God has commanded them to establish, and those who spread evil in the land will have God’s condemnation instead of reward and will face the most terrible end.” (Verse 25 of Surah Ar’Ra’ad)
