The grace of faith, by which the elect are enabled to believe so that their souls are saved, is the work of the Spirit of Christ in their hearts (2Co 4:13; Eph 2:8). Faith is ordinarily produced by the ministry of the Word (Ro 10:14, 17). By this same ministry and by the administration of baptism and the Lord’s supper, prayer, and other means appointed by God, faith is increased and strengthened (Lk 17:5; 1Pe 2:2; Ac 20:32).
By this faith Christians believe to be true everything revealed in the Word, recognizing it as the authority of God himself (Ac 24:14). They also perceive that the Word is more excellent than every other writing and everything else in the world (Ps 27:7-10; 119:72), because it displays the glory of God in his attributes, the excellence of Christ in his nature and offices, and the power and fullness of the Holy Spirit in his activities and operations. So they are enabled to entrust their souls to the truth believed (2Ti 1:12). They respond differently according to the content of each particular passage—obeying the commands (Jn 14:14), trembling at the threatenings (Isa 66:2), and embracing the promises of God for this life and the one to come (Heb 11:13). But the principal acts of saving faith focus directly on Christ—accepting, receiving, and resting upon him alone for justification, sanctification, and eternal life, by virtue of the covenant of grace (Jn 1:12; Ac 16:31; Gal 2:20; Ac 15:11).
This faith may exist in varying degrees so that it may be either weak or strong (Heb 5:13-14; Mt 6:30; Ro 4:19-20). Yet even in its weakest form, it is different in kind or nature (like all other saving graces) from the faith and common grace of temporary believers (2Pe 1:1). Therefore, faith may often be attacked and weakened, but it gains the victory (Eph 6:16; 1Jn 5:4-5). It matures in many to the point that they attain full assurance through Christ (Heb 6:11-12; Col 2:2), who is both the founder and perfecter of our faith (Heb 12:2).