“The faith which was once delivered unto the saints,” is not that grace of faith which “is the fruit of the Spirit,” but that doctrine and order of the gospel in which the salvation of God is made known to the saints in the world. This is that “mystery which hath been hid from ages and generations, but now is made manifest unto his saints,” and this mystery “is Christ in them the hope of glory.” (Eph. iii. 5; Col. i. 26, 27.) This doctrine of salvation by grace, and the order of the gospel, was delivered unto the saints on the day of Pentecost, when the gospel church was established. The apostles were charged with the authority to teach it to the saints, and to set all the commands of Jesus concerning the church in order, as judges sitting upon thrones, to judge the twelve tribes of Israel.
All this gospel system is made known to the faith of God’s people. It is not understood by the natural mind, but by an understanding especially given for this purpose. (1 John v. 20; Eph. i. 17-23.) This doctrine of God is spoken of as “the faith of the gospel.” Paul uses the word faith in this sense, as a system of faith, in Romans i. 5; xvi. 26; Gal. i. 23, and in other places. This faith, or doctrine, in which the eternal salvation of the saints is declared and made manifest in the world, is of the utmost importance and value to the saints. It is more than all the world to them. It sets forth and declares “the wisdom of God in a mystery, even the hidden wisdom, which God ordained before the world unto our glory.”–I Cor. ii. 7.
It declares the ways and wisdom of God in salvation, as contrasted with the ways and wisdom of men. It was once delivered unto the saints in the morning of the gospel dispensation, and it is needful that they earnestly contend for it, for the whole world, and all the influences of the world, are opposed to it.” – Silas Durand