Impeccability
Impeccability is an inability to sin, while sinlessness refers to an absence of actual sin. The Abrahamic religions teach impeccability to be an attribute of God. Logically God cannot sin: it would mean that God would act against God's own will and nature. Impeccability is therefore also attributed to Jesus Christ in Christianity. The Letter to the Hebrews asserts that Christ "did not sin". Islam further teaches a concept of, the sinlessness or impeccability of prophets, which has been compared to Papal infallibility in early Catholic doctrine.
Biblical and apocryphal writings
In the New Testament, the Letter to the Hebrews asserts that Jesus Christ "did not sin".The writer of the apocryphal Prayer of Manasseh states that Abraham, Isaac and Jacob did not sin against God.
Roman Catholic teachings
The Virgin Mary
The Roman Catholic Church teaches that Mary, mother of Jesus was, by a special grace of God, without sin throughout her life. This included the moment of her conception, so Mary was even miraculously preserved from original sin and its effects. Some theologians have asserted this special grace extended to impeccability ; others argue this could not be so: as a natural human being, she would have had free will and therefore the ability to sin but through her cooperation avoided it.Papacy
Impeccability is sometimes confused with infallibility, especially in discussions of papal infallibility. Impeccability is an attribute not claimed by the pope, and few would deny that there have been bad popes: Saint Peter himself denied Jesus three times. On the other hand, Pope Gregory VII, intellectual progenitor of the Ultramontanes and nemesis of the lay faction in the investiture controversy, voiced an assertion of papal prerogative beyond even the strongest of modern apologists:Nevertheless, in Catholic thought, the exemption of the See of Rome from all error extends only to its definitive teachings on faith and morals, not to its historical judgments. Similarly, papal sainthood does not suggest that popes are free from sin. Quite the contrary, popes frequent the sacrament of Reconciliation for the forgiveness of their sins, as all Catholics are required to do. While occupying the papal office, Pope Benedict XVI confessed his sins weekly.
Afterlife
Early Christians questioned whether the victorious saints in heaven could sin. Church Father and theologian Origen of Alexandria maintained that they could; official Roman Catholic doctrine holds that they cannot. Although Catholics believe in the gift of free will, saints in heaven already see God face to face and are incapable of sinning, i.e., they will necessarily remain in God. The Catechism of the Catholic Church states, in paragraphs 1045 and 1060, emphasis added:Thomas Aquinas taught that souls in Purgatory cannot sin, let alone the saints in heaven. This is the teaching of the Roman Catholic Church, although there are different opinions on the reasons for the impossibility to sin.
Protestant teaching
Evangelical writer Donald Macleod suggests that the sinless nature of Jesus Christ involves two elements. "First, Christ was free of actual sin." Studying the gospels there is no reference to Jesus praying for the forgiveness of sin, nor confessing sin. The assertion is that Jesus did not commit sin, nor could he be proven guilty of sin; he had no vices. In fact, he is quoted as asking, "Can any of you prove me guilty of sin?" in John 8:46. Secondly, he was free from inherent sin.Protestant Christian theology holds that Jesus died for all human sins.