I answer that, There are two ways of fulfilling the commandments of the Law.  The first regards the substance of the works, as when a man does works of justice, fortitude, and of other virtues.  And in this way man in the state of perfect nature could fulfil all the commandments of the Law; otherwise he would have been unable to sin in that state, since to sin is nothing else than to transgress the Divine commandments.  But in the state of corrupted nature man cannot fulfil all the Divine commandments without healing grace.  Secondly, the commandments of the law can be fulfilled, not merely as regards the substance of the act, but also as regards the mode of acting, i.e. their being done out of charity.  And in this way, neither in the state of perfect nature, nor in the state of corrupt nature can man fulfil the commandments of the law without grace.  Hence, Augustine (De Corrept. et Grat. ii) having stated that “without grace men can do no good whatever,” adds:  “Not only do they know by its light what to do, but by its help they do lovingly what they know.”  Beyond this, in both states they need the help of God’s motion in order to fulfil the commandments, as stated above (AA. 2, 3).

Reply Obj. 1:  As Augustine says (De Spir. et Lit. xxvii), “do not be disturbed at his saying that they do by nature those things that are of the Law; for the Spirit of grace works this, in order to restore in us the image of God, after which we were naturally made.”

Reply Obj. 2:  What we can do with the Divine assistance is not altogether impossible to us; according to the Philosopher (Ethic. iii, 3):  “What we can do through our friends, we can do, in some sense, by ourselves.”  Hence Jerome [Symboli Explanatio ad Damasum, among the supposititious works of St. Jerome:  now ascribed to Pelagius] concedes that “our will is in such a way free that we must confess we still require God’s help.”

Reply Obj. 3:  Man cannot, with his purely natural endowments, fulfil the precept of the love of God, as stated above (A. 3). ________________________

FIFTH ARTICLE [I-II, Q. 109, Art. 5]

Whether Man Can Merit Everlasting Life Without Grace?

Objection 1:  It would seem that man can merit everlasting life without grace.  For Our Lord says (Matt. 19:17):  “If thou wilt enter into life, keep the commandments”; from which it would seem that to enter into everlasting life rests with man’s will.  But what rests with our will, we can do of ourselves.  Hence it seems that man can merit everlasting life of himself.

Obj. 2:  Further, eternal life is the wage of reward bestowed by God on men, according to Matt. 5:12:  “Your reward is very great in heaven.”  But wage or reward is meted by God to everyone according to his works, according to Ps. 61:12:  “Thou wilt render to every man according to his works.”  Hence, since man is master of his works, it seems that it is within his power to reach everlasting life.