Acts 4:11–12, “This is the stone which was set at naught of you builders, which is become the head of the corner. Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.” We cannot, however, believe on the name of Christ, except by hearing his merit preached, and by embracing it. By faith in the name of Christ, therefore, and not by confidence in our own works, are we saved. For the word, name, here signifies the cause through and for which salvation comes. Therefore, the praise and confession of the name of Christ, signifies trust in him, who alone is called, who is Christ, being the cause of our salvation and the treasure by which we are redeemed. Acts 15:9, “He purified their hearts by faith.” Hence the faith, spoken of by the Apostles, is not a mere historical knowledge, but a powerful and vigorous operation of the Holy Ghost, which changes the heart. Hab. 2:4, “The just shall live by his faith.” Here we are told in the first place, that the just are made just by faith, if they believe that God is merciful through Christ; and secondly, that faith produces life. Faith alone gives peace and joy to the heart and conscience, and eternal life, which begins here on earth.
Isa. 53:11, “By his knowledge shall my righteous servant justify many.” Now what is the knowledge of Christ, but a sense of his benefits and his promises, which he preached and made known to the world ? To have a knowledge of these benefits is, to believe truly in Christ, to believe that God will certainly give what he has promised through Christ. But the Scriptures abound with such declarations and testimony. They treat of both, the law of God and his promises. Now the promises speak of the forgiveness of sins and the reconciliation of God through Christ. (Henkel Translation, p. 176-177).