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 offence, 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 being lost now on the one side, or for the believer 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.