Taken from the original, unabridged edition of "Rabbi" John Duncan's In the Pulpit and At the Communion Table, edited by David Brown (Edinburgh: Edmonston and Douglas, 1874), 123-28.
Westminster Shorter Catechism Question 31: "Effectual calling is the work of God's Spirit, whereby, convincing us of our sin and misery, enlightening our minds in the knowledge of Christ, and renewing our wills, He doth persuade and enable us to embrace Jesus Christ, freely offered to us in the Gospel."
(1.) It is Christ that is offered; (2.) He is freely offered; (3.) It is in the Gospel that He is freely offered. The word "Gospel" is used sometimes in a wider, sometimes in a more restricted sense. The "Gospel" may mean and embrace the whole of the New Testament Revelation: it may also be put widely for the whole Revelation of God, so far as given with evangelical design and tendency. In its wider sense, the Gospel comprehends narrative, testimony, promise, doctrine; but also commands and threatenings - all that appertains to or is connected with the Gospel. But strictly so called, the Gospel is God's testimony concerning His Son - His gift of Jesus Christ as the appointed Saviour. Hence the Gospel, in the strictest sense, hath no commands or threatenings. There is a command of God that we believe in the name of Christ; but this properly belongs to the head of law - a law of God in regard to the Gospel. And that law hath a threatening - "He that believeth not shall be damned." This, then, is the Gospel strictly: "The Son of Man is come to seek and to save that which was lost;" "Christ died, the just for the unjust, that He might bring us to God;" "This is a faithful saying, and worthy of all acceptation, that Christ Jesus came into the world to save sinners, of whom I am chief;" "Whom God hath set forth to be a propitiation through faith in His blood;" "I have given Him to be a Witness to the people." Such passages contain simply and purely Gospel - good news.
Other passages, where faith is mentioned, are two-fold: one class exhibiting our warrant to believe in Christ: and this faith which bringeth salvation may be held as belonging to the head of "Gospel" strictly so called. But passages which put faith in the light of obligation belong rather to the head of the law which God hath made about the Gospel. Thus I take the precision of language on the part of the "Marrow-men," who were in the main on the side of Gospel truth - if it be not carried to captiousness; for that too is a fault - construing loose language as if it were grave error: These make such passages as this - "Believe on the Lord Jesus Christ, and thou shalt be save," in so far as Christ saves, to be pure Gospel; but in so far as believing is by the authority of God, which binds men to believe, they hold it to belong to the head of law. So in texts where "faith" occurs, they distinguish between the Gospel and the law of the Gospel. The Gospel contains the doctrine of salvation and the sinner's warrant to believe. It is in the Gospel that Christ is offered, and that is the warrant of our faith.
We must beware of substituting any other warrant for trusting in Christ than the Gospel. Christ must have the place given to Him, the Spirit the place given to Him, the Gospel the place given to it. The work of the Spirit - in convincing, enlightening, enabling to believe in Christ - must never be put as our warrant to believe on Christ. The formal reason must not be because we are convinced, enlightened, persuaded; that is not the ground why we trust, but simply that He is revealed to us in the Gospel. Christ is the Object of saving faith, and God in Him; the Spirit is the efficient Cause, the word of the truth of the Gospel is the Warrant. In believing on Christ we do it not on the ground of any specialty, but on the ground of that which is common to us with mankind. Thus all self-confidence is guarded against. A sinner convinced is no more entitled to believe by His being convinced than an unconvinced sinner - the enlightened, the persuaded, no more than if they were not so. Nothing that distinguishes from all the world, or from any other men, can give us a title; and for this very good reason that a full title is given independent of all that. If it were otherwise, the doctrine of merit is introduced the moment that is admitted. In short, we obscure and destroy the glorious Gospel of the grace of God, and its absolute freeness, unless we take in that not only is it no presumption to believe, but that it is a positive law. All such ideas of warrant resting upon a certain condition of mind is pernicious, as a dark cave for a soul to retreat into and defend itself against the authority of God to command faith.
I once had a discussion on this point with a person in the West Highlands, a man of considerable knowledge, and not without seriousness. I asked, was Christ offered to him? He was silent. To whom, then, was He offered? He answered to those wishing to receive Him. Now that was a complete subterfuge. So long as a man is in that condition of mind he is inexpugnable. If Christ were offered only to the wishing, then in not being willing there can be no unbelief, for there is no offer. If there be in the Gospel a real offer of Christ, then is there in the Gospel that which demands, on the hearing of it, the acting of human volition. Every hearing of the Gospel demands human volition. A reception by one involves the alternative of rejection by those who receive it not. Which do we do? To deal honestly in offering it to others, we must first have received it ourselves.
Although it be true that the elect only believe unto salvation, yet it is the convinced sinner, as such, and not the elect sinner, as such, that savingly believes. Yet the Gospel being offered to all mankind sinners, God's elect in believing do condemn the world of unbelievers, because they receive Christ on no special ground, but offered to them as, and in common with, others. The work of God's Spirit, in convincing of sin and misery, enlightening the mind in the knowledge of Christ, renewing the will, and persuading and enabling them to embrace Christ, is special to God's elect: but their being saved is not on the ground of their being so, but because they believe on Jesus Christ as perishing sinners like others.
Let us put this to ourselves first, and to the people next. Shall we condemn the world of the unbelieving? or shall the company of believers condemn us? If the truth be as we put it, either every believing man should condemn me, for he believed on what was common to us both, or else I should condemn every unbelieving man, for I believed what would have saved them if they had believed it. Let us mark now how the Gospel presses upon human volition. I speak not now of difficulties which may be raised to the [extent of the] Atonement, but I would that we should remember that what is offered is not a doctrine but a Person. If it be the case that Christ invites every sinner to His fellowship and salvation, inviting all, and promising to every coming sinner, then clearly there must of necessity be the act of the will. If there were but a bare doctrine, veracity only would have to be considered; but here there is the social act of trusting.
How glorious a plan is the blessed Gospel! So free that it secures the salvation of every hearer of the Gospel, provided he be not a rejector of it! The Gospel saves all who hear it - save those who reject it. It saves none but by positive reception: none are lost but by positive rejection of it. Men evangelized cannot go to hell but over the bowels of God's mercies. They must wade to it through the blood of Christ, and trample that blood under foot. And what an act of contempt against the Persons of the Godhead! Oh, what strength is in the human will! How great power men have to put away the grace of the Gospel!
But we cannot help dealing with the Gospel. It necessitates that we deal with it every time it comes in contact with us: every hearing of it must be attended, on our part, either by faith or by unbelief. And if it contain an offer of Christ, then unbelief comprehends not only rejection by the understanding as to testimony, but the action of the will as regards the offer. And the belief in the Gospel is not simply a belief that the offer is made, but an embracing of that offer - not merely a belief that Jesus is the Christ, and that if I take Him I shall be saved, but an actual receiving of Him, a willingness to have, corresponding with His believing willingness to give.
If these things be so, you see what lies suspended on the action of the human will. And yet, if all were left to fallen man, the multitudes and the word of God show how it would be. The fact that the willingness to receive the Gospel, though it be a fair demand of God on His fair offer, is brought out to be the fruit of the renovation of a man's will by the Holy Ghost, shows how it would be. And so the two ends of the Question begin to come together: the man is thus "persuaded and enabled to embrace Jesus Christ, freely offered to him in the Gospel."
We have thus seen some outline of the Gospel - what is it, its bearing on human volition, necessitating an alternative of faith or unbelief in all who hear it.