In the Old Testament there is no original sin. Everybody is responsible for his own sin. Only God can forgive God by His Grace. To expatiate small offenses sacrifice is required. The blood shed is the ransom of the sin committed.
In the Psalms, only God can forgive sins of the penitent.
In Christianity, Paul's teaching prevails according to which Adam had sinned and his sin is transmitted to his descendants as original sin. Lord Jesus sacrifices himself as a ransom and saved mankind from its sins. God empowered Jesus to pardon all sins. The Pope and the Priests, in their capacity of representatives of Jesus, have the authority to forgive sinners.
In the Qur'an man is considered to have been created without original sin. Sins committed afterwards can be forgiven by the Creator only. Jesus Christ is a servant and a prophet of God. God had given delegated no one to forgive on His behalf.