De natura et gratia libri III, cum Apologia contra Catharinum

This disposition or preparation is followed by justification itself, which is not the remission of sins alone, but also the sanctification and renewal of the inner man through the voluntary reception of grace and of gifts, whereby man from unjust becomes just, and from an enemy a friend, so that he may be an heir according to the hope of eternal life. The causes of this justification are: the final cause indeed the glory of God and of Christ, and eternal life; the efficient cause truly the merciful God, who freely washes and sanctifies, sealing and anointing with the Holy Spirit of promise, who is the pledge of our inheritance. The meritorious cause however is his most beloved only-begotten Son, our Lord Jesus Christ, who, when we were enemies, on account of the exceeding charity with which he loved us, merited justification for us by his most holy passion on the wood of the cross, and satisfied God the Father for us; the instrumental cause likewise the sacrament of baptism, which is the sacrament of faith, without which no one has ever obtained justification. Finally, the unique formal cause is the justice of God, not that by which he himself is just, but that by which he makes us just: namely, that by which, gifted by him, we are renewed in the spirit of our mind, and are not only reputed, but are truly named and are just: receiving justice in ourselves, each one according to his own measure, which the Holy Spirit distributes to each as he wills, and according to each one's own disposition and cooperation. For although no one can be just unless the merits of the passion of our Lord Jesus Christ are communicated to him, this nevertheless happens in the justification of the impious when, by the merit of that same most holy passion, through the Holy Spirit, the charity of God is poured into the hearts of those who are justified, and cleaves to them. Hence in justification itself, together with the remission of sins, man receives all these things infused at once through Jesus Christ, to whom he is joined: faith, hope, and charity. For faith, unless hope and charity be added to it, neither unites one perfectly with Christ, nor makes him a living member of his body. For which reason it is most truly said that faith without works is dead and idle, and that in Christ Jesus neither circumcision avails anything, nor uncircumcision, but faith which works through charity. This faith, before the sacrament of baptism, from the tradition of the Apostles, the catechumens ask of the Church when they ask for the faith that bestows eternal life, which faith without hope and charity cannot bestow. Hence they immediately hear the word of Christ, If you wish to enter into life, keep the commandments. Therefore, receiving true and Christian justice, they are commanded, as soon as they are reborn, to preserve it, as a first garment in place of that which Adam by his disobedience lost for himself and for us, given to them through Christ Jesus, pure and spotless, so that they may bear it before the tribunal of our Lord Jesus Christ and have eternal life.