This brief article is the fourth of six parts of Ursinus' commentary on Question 91 of the Heidelberg Catechism: "But what are good works?" The entire work is The Commentary of Dr. Zacharias Ursinus on the Heidelberg Catechism (Phillipsburg, NJ: Presbyterian & Reformed, n.d.; a reproduction of the Second American Edition which was printed at Columbus, OH, 1852).
If our works were not pleasing to God, they would be performed to no purpose. We must, therefore, know in what way it is that they please God. As they are imperfect in themselves, and defiled in many respects, they cannot of themselves please God, on account of his extreme justice and rectitude. Yet they are, nevertheless, acceptable to God in Christ the Mediator, through faith, or on account of the merit and satisfaction of Christ imputed unto us by faith, and on account of his intercession with the Father in our behalf. For just as we ourselves do not please God in ourselves, but in his Son, so our works, being imperfect and unholy in themselves, are acceptable to God on account of the righteousness of Christ, which covers all their imperfection or impurity, so that it does not appear before God. It is necessary that the person who performs good works should be acceptable to God; then the works of the person are also accepted; otherwise, when the person is without faith, the best works are but an abomination before God, inasmuch as they are altogether hypocritical. As now the person is acceptable to God, so are the works. But the person is acceptable to God on account of the Mediator; that is, by the imputation of the merit and righteousness of Christ, with which the person is covered as with a garment in the presence of God. Hence the works of the person are also pleasing to God, for the sake of the Mediator. God does not look upon and examine our righteousness and imperfect works as they are in themselves, according to the rigor of his law in respect to which he would rather condemn them; but he beholds and considers them in his Son. It is for this reason that God is said to have had respect to Abel and his offering, viz.: in his Son, in whom Abel believed; for it was by faith that he presented his sacrifice (Gen. 4:4, Heb. 11:4). So Christ is also called our High Priest, by whom our works are offered unto God. He is also called the altar, on which our prayers and works being placed, they are acceptable unto God, which otherwise would be detestable in his sight. It follows, therefore, that every defect and every imperfection respecting ourselves and our works is covered, and, as it were, repaired in the judgment of God, by the perfect satisfaction of Christ. It is in view of this that Paul says, "That I may be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith" (Phil. 3:9).
