Of Pelagius's early life we know little; he probably died early in the fifth century. This much is known, that he was a monk in the great monastery at Bangor, Wales, and that his real name was Morgan. He had a close follower named Celestius, a native of Ireland. These two men went to Rome, then to Africa, and then to Jerusalem, spreading their evil doctrine. Grace to them was nothing more than a call to man to exercise his best efforts toward God. We shall quote the words of another about the Pelagian heresy: “The fundamental error of the monk Pelagius was the denial of our total corruption by sin derived from Adam and met only by the death and resurrection of the second Man, the last Adam. Hence, he asserted liberty as now true of all men, not merely in the sense of exemption from external restraint, but of freedom within the nature as to good and evil, denying thus in the race internal bondage to sin. So he appears to have seen little more in grace, even in its Christian application, than pardon for this or that offense, not the impartation to the believer of a new nature, in virtue of which he does not practice sin, because he is born of God. Thus, no room was left in the Pelagian scheme for man's being lost now on the one side, or for the believer's being saved now on the other. In fact, the race was conceived to be in an innocence like the primeval state of Adam, till each sinned and thus fell under guilt and its consequences. The Pelagians denied the imputation of Adam's sin, seeing no more than the influence of a bad example. As the moral ruin of man was thus enfeebled and the relation of the head lost, so on the other hand under grace were reckoned all the natural endowments of the human family, as well as the supernatural. Hence, conscience, law and gospel were regarded as different methods, as well as advancing stages of righteousness, in every case the means and operations of grace being effectual only according to the measure of the tendencies of the will. Again, the redemption of Christ became thus, if not an amelioration, certainly an exaltation and transfiguration of humanity. Christ Himself was but the highest pattern of righteousness, some before Him having perfectly kept the moral law, and others since being stimulated by His work, love and example to the evangelical counsels of moral perfection beyond law.”
It should be apparent to the most superficial reader of the above that Pelagius denied both the fall and utter ruin of man on the one hand, and the only way of redemption through the work of Christ for and the operation of the Spirit in its application to man on the other. It was a deadly error that nullified the necessity of the whole counsels and operation of the grace of God. It would have foredoomed the creature to remain in his alienation from God, although this alienation is denied.
If man is not lost, then the Lord Jesus needed not to come "to seek and to save that which was lost" (Luke 19:1010For the Son of man is come to seek and to save that which was lost. (Luke 19:10)). If a man could elevate himself, by the exercise of his own will and by good thus performed, back to God, then God needed not to send His beloved Son to suffer and die. But God has faithfully told us that we were not only lost and without any strength to do anything about it, but that we were morally dead—dead toward God—that there is not one movement of our hearts toward Him (Romans and Ephesians). Being thus in such a plight, we needed One to rescue us, to save us, and we needed the impartation of life, an entirely new life.