by Louis Berkhof
One of the most important points of the controversy between the Church of Rome and the Reformers, and between Reformed theology and the Arminians, concerned the ground of justification. With respect to this the Reformers taught:
1. Negatively, that this cannot be found in any virtue of man, nor in his good works. This position must also be maintained at present over against Rome and the Pelagianizing tendencies of various Churches. Rome teaches that the sinner is justified on the basis of the inherent righteousness that has been infused into his heart, and which, in turn, is the fruit of the co-operation of the human will with prevenient grace. This applies to what is called the first justification; in all following justification the good works of man come into consideration as the formal cause or ground of justification. It is impossible however, that the inherent righteousness of the regenerate man and his good works should be constitute the ground of his justification, for (a) this righteousness is and remains during this life a very imperfect righteousness; (b) it is itself already the fruit of the righteousness of Christ and of the grace of God; and (c) even the best works of believers are polluted with sin. Moreover, Scripture teaches us very clearly that man is justified freely by the grace of God, Rom. 3:24, and that he cannot possibly be justified by the works of the law, Rom. 3:28; Gal. 2:16; 3:11.
2. Positively, that the ground of justification can be found only in the perfect righteousness of Jesus Christ, which is imputed to the sinner in justification. This is plainly taught in several passages of Scripture, such as Rom. 3:24; 5:9,19; 8:1; 10:4; 1 Cor. 1:30; 6:11, 11Cor. 5:21; Phil. 3:9. In the passive obedience of Christ, who became a curse for us (Gal. 3:13) we find the ground for the forgiveness of sins; and in His active obedience, by which He merited all the gifts of grace, including eternal life, the ground for the adoption of children, by which sinners are constituted heirs of life eternal. The Arminian goes contrary to Scripture when he maintains that we are accepted in favor by God only on the ground of our faith or evangelical obedience.
Louis Berkhof, Systematic Theology