1. Pope: Ancient heresy plagues modern Church
Pelagius . . . believed that “man could, by the natural power of free will and without the necessary help of God’s grace, lead a morally good life” . . . . Indeed, Pelagius believed that several Old Testament figures, without the help of grace, led sinless lives.
Pelagius held that although Adam offered a bad example, his sin altered only his own relationship with God, and that consequently there is no original sin from which Adam’s descendants need to be redeemed. Pelagius’ followers thus denied that baptism cleanses the soul from original sin and also denied that the sacrament elevates the baptized into a state of supernatural friendship with God. Pelagius did believe that God wished to make it easier for human beings to lead sinless lives, and so God instructed people through the law of Moses and by Christ’s teaching and good example. [period]
Pelagius held, however, that human beings do not need the interior assistance of God’s grace to avoid sin and lead holy lives; instead, he believed that holiness is attained through one’s unaided free will.
2. Pelagianism – Wikipedia
Pelagianism is the belief that original sin did not taint human nature and that mortal will is still capable of choosing good or evil without special divine aid. This theological theory is named after the British monk Pelagius (354–420 or 440), although he denied, at least at some point in his life, many of the doctrines associated with his name. Pelagius was identified as an Irishman by Saint Jerome. Pelagius taught that the human will, as created with its abilities by God, was sufficient to live a sinless life, although he believed that God’s grace assisted every good work. Pelagianism has come to be identified with the view (whether taught by Pelagius or not) that human beings can earn salvation by their own efforts.
3. The False Teachers: Pelagius – Tim Challies [a Protestant view]
Pelagius believed that man had not been entirely corrupted by Adam’s fall and that he could, by his own free will, do works that pleased God, and thus be saved. This led Pelagius to deny the doctrines of original sin and predestination, and to deny the need for special grace to be saved. Essentially, he believed that man is basically good and moral and that even pagans can enter heaven through their virtuous moral actions.
4. Pelagius Lives – Catholicism.org
Pelagius was a rationalist and, consequently, had to confront in his day the same perplexing question confronting ours: If all men had indeed inherited original sin, and therefore would suffer the loss of the Beatific Vision unless they embraced the One True Faith and were baptized, what of the vast numbers of men at the ends of the earth who had never heard of Christ? Would it not be unjust of God to send such men to hell?
Etc. etc. etc.