The Islamic concept of repentance for any sins and misdeeds is called tawba. It is a direct matter between a person and God, so there is no intercession or formal, ecclesiastical confession to a religious leader.
However, There is also no concept of original sin in Islam, thus the need for atonement, or ecclesiastical confession.
The biblical basis for the belief is generally found in Genesis 3 (the story of the expulsion of Adam and Eve from the Garden of Eden), in a line in Psalm 51:5 ("I was brought forth in iniquity, and in sin did my mother conceive me"), and in Paul's Epistle to the Romans, 5:12-21 ("Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all people, because all sinned").
This belief began to emerge in the 3rd century, but only became fully formed with the writings of Augustine of Hippo (354–430 AD), who was the first author to use the phrase "original sin" (Latin: peccatum originale). Influenced by Augustine, the councils of Carthage (411–418 AD) and Orange (529 AD) brought theological speculation about original sin into the official lexicon of the Church.
Here we would like to share the verses from Surah 2. Al Baqarah (The Cow), wherein it is clearly stated that upon seeking forgiveness from Allah, Adam was forgiven, these no question arises about that sin carried forward by every newly born:
(2:36) But Satan caused both of them to deflect from obeying Our command by tempting them to the tree and brought them out of the state they were in, and We said: “Get down all of you; henceforth, each of you is an enemy of the other, and on earth you shall have your abode and your livelihood for an appointed time.”
(2:37) Thereupon Adam learned from his Lord some words and repented and his Lord accepted his repentance for He is Much-Relenting, Most Compassionate.
(2:38) We said: “Get you down from here, all of you, and guidance shall come to you from Me: then, whoever will follow My guidance need have no fear, nor shall they grieve.
(2:39) But those who refuse to accept this (guidance) and reject Our Signs as false are destined for the Fire where they shall abide for ever.”
Read the explanation of these verses from our earlier post: Surah Al Baqarah - The Cow: 2nd Chapter of Qur'an (Exegesis - Introduction)
If a man commits a sin, he is directed to repent immediately and then seek forgiveness from Allah. And Allah promises umpteen number of times that if His servant asks for forgiveness after sincere repentance, He would certainly forgive him.
"And those who having done something to be ashamed of or wronged their own souls earnestly bring Allah to mind and ask for forgiveness for their sins and who can forgive sins except Allah? And are never obstinate in persisting knowingly in (the wrong) they have done." (3:135)
- And hasten to the forgiveness of your Lord, and paradise (Surah 3. Al-i'Imran:133)
- Remember Allah Instantly if you sin and implore forgiveness (Surah 3. Al-i'Imran:135)
- And whoever does evil, but seeks Allah's forgiveness, he will find Allah Oft-Forgiving, Most Merciful (Surah 4. An-Nisaa:110)
- Allah's acceptance of repentance is only for those who commit evil and then soon repent (Surah 4. An-Nisaa:17-18)
- Seek forgiveness of Allah and turn to Him in repentance - Surely Allah is Ever Merciful, Most Loving (Surah 11 Hud verse 90)
- Our Lord! Forgive me and my parents and the believers on the Day of Reckoning (Surah 14. Ibrahim:41)
- Allah will forgive those who guard their chastity and remember Him much (Surah 33. Al-Ahzab:35)
- The Verse of Mercy: Those who have committed excesses should not despair of Allah's Mercy - Surely Allah forgives all sins (Surah 39. Az-Zumar:53)
- Our Lord! Forgive those who repent and follow Your Path (Surah 40. Al-Mu'min:7)
- Surely your Lord is abounding in forgiveness (Surah 53. An-Najm:32)
- Believers, turn to Allah in sincere repentance; for He may expunge your evil deeds (Surah 66. At-Tahrim:8)
May Allāh (سبحانه و تعالى) help us understand Qur'ān and follow the Sunnah of Prophet Muhammad ﷺ, which is embodiment of commandments of Allah contained in the Qur'ān. May Allah help us to be like the ones He loves and let our lives be lived helping others and not making others' lives miserable or unlivable. May all our wrong doings, whether intentional or unintentional, be forgiven before the angel of death knocks on our door.