5. Fifthly, I shall close this chapter with a brief answer to some queries relating to faith, repentance, and good works; as, to what they belong, whether to law or gospel.
5a. Whether faith is a duty of the moral law, or is to be referred to the gospel? to which it may be answered, that as the law is not of faith, so faith is not of the law. There is a faith indeed which the law requires and obliges to, namely, faith and trust in God, as the God of nature and providence; for as both the law of nature, and the law of Moses, show there is a God, and who is to be worshipped; they both require a belief of him, and trust and confidence in him; which is one part of the worship of him enjoined therein: moreover the law obliges men to give credit to any revelation of the mind and will of God he has made, or should think fit to make unto them at any time; but as for special faith in Christ as a Saviour, or believing in him to the saving of the soul; this the law knows nothing of, nor does it make it known; this kind of faith neither comes by the ministration of it, nor does it direct to Christ the object of it, nor give any encouragement to believe in him on the above account; but it is a blessing of the covenant of grace, which flows from electing love, is a gift of God's free grace, the operation of the Spirit of God, comes by the hearing of faith, or the word of faith, as a means, that is, the gospel; for which reason, among others, the gospel is so called; and it is that which points out Christ, the object of faith; and directs and encourages sensible sinners under a divine influence to exercise it on him; its language is, "believe on the Lord Jesus Christ, and thou shalt be saved", Ac 16:31".
5b. Whether repentance is a doctrine of the law or of the gospel? the answer to which is, that such who sin ought to repent of sin; this God has commanded, the law of nature teaches; and so far as this is to be considered as a duty incumbent on men, it belongs to the law, as all duty does; but then the law makes no account of repentance for sin; nor does it admit of it as a satisfaction for it; nor gives any encouragement to expect that God will receive repenting sinners into his grace and favour upon it; this is what the gospel does, and not the law; the law says not, repent and live, but do and live. Moreover, there is what may be called a legal repentance and contrition; for by the law is the knowledge of sin, without which there can be no repentance; and it works a sense of wrath in the sinners conscience, and a fearful looking for of judgment and fiery indignation from an incensed God; but if it stop here, it will prove no other than a worldly sorrow, which worketh death. The Spirit of God may make use of this, and go on and produce spiritual repentance, such a repentance as is unto life, even life eternal; and unto salvation, which needeth not to be repented of: but such a repentance is not the work of the law; for life and salvation come not by any work of the law; but true repentance, which has salvation annexed to it, is, as faith, a blessing of the covenant of grace; a grant from God, a gift of Christ as a Saviour, and with it remission of sins; a grace produced in the soul by the Spirit of Christ, by means of the gospel, which only encourages to the exercise of it; see "Acts 5:31 11:18 2Co 7:10 Ga 3:2". And so is a doctrine of the gospel, and not of the law, as appears from the ministry of John the Baptist, the forerunner of Christ, who exhorted and encouraged to repentance from gospel motives; and preached the baptism of repentance for the remission of sins, "Matt 3:2 Mr 1:4". But what has the law to do either with baptism or the remission of sins? His ministry was evangelical, and ran in the same strain with the apostles, as appears from their answer to a question put to them; "Men and brethren, what shall we do?" A serious question, put upon thought and reflection by persons upon the bottom of a covenant of works {1}, as the Jews rally were; and especially under a sense of guilt, as those were, desirous to know what must be done by them, that they "might be saved"; as it may be supplied from the jailor's words, when in the same case; or whereby they might make atonement for, and obtain the pardon of so great a sin, of which they were guilty {2}: to which a proper answer is returned, putting them off of legal works for such purposes, and directing them to evangelical ones; "Repent and be baptized, everyone of you, for the remission of sins", "Acts 2:37,38". And this is also clear from the story of Christ himself; who came, not to call the righteous, but sinners, to repentance; which was not a legal, but evangelical repentance. He began his ministry thus; "Repent, and believe the gospel", see "Matt 9:13 Mr 1:15". With which agrees the ministry of the apostles in general; who, by the direction of Christ, preached repentance and remission of sins in his name; which most certainly was the gospel; the one, as well as the other, a doctrine of the gospel, "Luke 24:47". And the apostle Paul, who was a most evangelical preacher, divides his whole ministry into these two parts; "Repentance towards God, and faith towards our Lord Jesus Christ", "Acts 20:21".
5c. Whether good works belong to the gospel, or to the law? or rather, whether there are any works that belong to the gospel distinct from the law? to which it may be replied, That the gospel, taken in a large sense, as has been observed in the beginning of this chapter, includes both the doctrines and ordinances of the gospel; and the one, as well as the other, are taught, and directed to be observed; yea, all good works, which the law requires, are moved and urged unto in the ministry of the gospel, upon gospel principles and motives: the gospel of the grace of God, which brings the good tidings of salvation, instructs and urges men to do good works, and to avoid sin, "Titus 2:11,12 3:8". But the gospel, strictly taken, is a pure declaration of grace, a mere promise of salvation by Christ. All duty and good works belong to the law; promise and grace belong to the gospel; the works of the law, and the grace of the gospel, are always opposed to each other, "Rom 3:20,24,28 Eph 2:8". And if there were any works distinct from the law, and not required by it, which, if not performed, would be sin; then the apostle's definition of sin, as a transgression of the law, would not be a full and proper one, "#1Jo 3:4" since then there would be sins which were not transgressions of the law; wherefore, as all evil works are transgressions of the law, all good works are required and enjoined by it.
-John Gill, The Body of Divinity: Of the Gospel