Holy Scripture does not always use the term faith in the same meaning. In some passages it denotes faithfulness, or trustworthiness, as found both in God and in man. Faith in this sense is applied to God in Rom. 3, 3 and to the regenerate in Gal. 5, 22. Faith in the sense of faithfulness is in believers a fruit of justifying faith and belongs into the article of sanctification and not into that of justification. In other words, faith justifies and saves, not as faithfulness, or trustworthiness, that is to say, not as a good work in the regenerate, but as the receiving means (medium λητπιχόν) by which the believer appropriates to himself the grace of God and the merits of Christ offered to him in the Gospel. In its proper sense, that is, regarded as the means by which the believer receives divine grace, faith always denotes trust in the merciful promises of God in Christ Jesus, Mark 16, 15. 16; 1,14.15; 9, 23. 24; Heb. 11,1. Or we may say, justifying faith in this sense is always fides passiva, which saves not in view of its own worth as a virtue, but in view of its object, namely, the grace of God and the merits of Christ, which it appropriates. Cf. the Apology: “Faith justifies and saves, not on the ground that it is a work in itself worthy (opus per sese dignum), but only because it receives the promised mercy.” (Trigl., p. 137.)
In a few passages of Scripture, such as Acts 6, 7; Gal. 1, 23; Jude 3. 20; etc., the term faith denotes the Christian doctrine (fides, quae creditur), or the Gospel of salvation by grace through faith in Christ. Faith in this sense is called objective faith (fides cbiectiva) in contradistinction to justifying faith, which is termed subjective faith (fides subiectiva), since it is found in the heart of the individual believer. To understand this use of the term faith, we must remember that personal trust in the grace of God for Christ’s sake (fiducia) is indeed the central article of the entire Christian religion, so that in this case the Christian doctrine receives its name from its chief characteristic. Whenever our dogmaticians speak of fides, quae creditur, they mean the doctrine of salvation which must be believed; when they speak of fides, qua creditur, they mean justifying or saving faith, that is, the receiving means of salvation (medium ληπτικόν).— In passing, it may be said that some exegetes aver that πίστις is in the New Testament is never employed in an objective, but only in a subjective sense, so that πίστις always denotes the fides, qua creditur, never the fides , quae creditur. (Cp. Christl. Dogmatik, Vol. II, p. 540 ff.)
With respect to the terminology of the Church on this point we may note, by way of review, the following: 1) Implicit faith is alleged assent to doctrines though these may not be known to the individual (fides carbonaria, Koehlerglaube: “I believe what the Church teaches”). 2) Explicit faith (fides explicita) is assent to doctrines distinctly known. 3) Justifying, or saving, faith is personal trust in the gracious remission of sin for Christ’s sake. 4) Direct faith is faith which lays hold of the grace of God in Christ Jesus. Justifying faith is always direct. 5) Reflex, or discursive, faith is faith by which the regenerate perceives that he believes. Infants, and adults while asleep or unconscious, have direct faith, but not reflex or discursive faith. 6) General faith (fides generalis) is assent to all truths revealed in God’s Word. 7) Special faith (fides specialis) is justifying faith, or personal trust in the grace of God for Christ’s sake. The object of general faith is the whole Bible ; that of special faith is the promise of the Gospel concerning the grace of God and the remission of sins through Christ’s vicarious satisfaction. 8) A false, or vain and dead, faith is called faith only equivocally, because it is nothing but an empty boast or a bold presumption upon the mercy and grace of made by impenitent men (Hollaz). 9) God Faith is said to be weak, or infirm, when either the knowledge of Christ is weak or the confidence in Christ is infirm. 10) Faith is strong when either the knowledge of Christ, or the trust in Him, is strong. 11) Objective faith is the doctrine which is believed. 12) Subjective faith is the faith by which one believes. 13) Historic faith is mere knowledge of Christ without personal trust in Him. 14) General assent is that by which the Gospel promises are regarded as true. 15) Special assent is that by which the individual believer regards the gracious promises of the Gospel as applying to him personally. 16) Saving faith is always fides actualis, that is, an active confiding on the part of the believer in the grace of God.
All these terms express truths that should be kept in mind in connection with the doctrine of saving faith. Let the student, however, remember that some of these terms have not always been used in precisely the same sense, so that their definitions as given by different dogmaticians may vary.