What is meant by it?
To understand the meaning of irresistible grace we must go back in history to the time of the Arminian controversy. The very term irresistible cannot be understood, except in that light.
The Arminians taught resistible grace. In their third article they seemed to maintain an orthodox doctrine of man’s depravity, although more than appearance this was not. And in their fourth article they made it very plain that the grace of God in their system of doctrine is dependent on the will of man. Man, after all, is able to resist the operation of God’s grace; and if he is able to resist, he is also able not to resist. The choice rests with him, and the efficacy of God’s grace depends on the willingness or unwillingness of the sinner.
This is very plain when one reads Articles 3 and 4 of the Arminians together:
3. That man has not saving faith of himself, nor of the energy of his free will, in as much as he, in the state of apostasy and sin, can of and by himself neither think, will, nor do any thing that is truly good (such as saving faith eminently is); but that it is needful that he be born again of God in Christ, through His Holy Spirit, and renewed in understanding, inclination, or will, and all his powers, in order that he may rightly understand, think, will, and effect what is truly good, according to the Word of Christ, John xv. 5: ‘Without Me ye can do nothing.’
4. That this grace of God is the beginning, continuance, and accomplishment of all good, even to this extent, that the regenerate man himself, without prevenient or assisting, awakening, following and co-operative grace, can neither think, will nor do good, nor withstand any temptations to evil; so that all good deeds or movements, that can be conceived, must be ascribed to the grace of God in Christ. But as respects the mode of the operation of this grace, it is not irresistible, in as much as it is written concerning many, that they have resisted the Holy Ghost, Acts vii., and elsewhere in many places.
Bear in mind that when the Arminian speaks of “resistible” and “irresistible” he does not have in mind merely the idea that the natural man attempts and strives to oppose and counteract and overcome the power of God’s grace, but that he successfullyopposes the grace of God, so that he is not converted to God. This is plain from the articles quoted above, but even more clear from the written opinions of the Remonstrants which were submitted to the Synod of Dordrecht, especially from Paragraphs 5 and 6:
5. The efficacious grace by which anyone is converted is not irresistible, and although God through the Word and the inner operation of His Spirit so influences the will that he both bestows the power to believe, or supernatural powers, and indeed causes man to believe; nevertheless man is able of himself to despise this grace, not to believe, and thus to perish through his own fault. (italics added)
6. Although according to the altogether free will of God the disparity of divine grace may be very great, nevertheless the Holy Spirit bestows, or is ready to bestow, as much grace upon all men and every man to whom God’s Word is preached as is sufficient for the furtherance of the conversion of men in its steps; and therefore not only do they obtain sufficient grace unto faith and conversion whom God is said to be willing to save according to the decree of absolute election, but also they who are not actually converted. (italics added)
It is over against this doctrine that the Fourth Point of Calvinism maintains the truth of what has come to be known as “Irresistible Grace.”
And yet that expression does not occur in our Canons. Neither in the title of the Third and Fourth Heads of Doctrine nor in the articles themselves does the term occur.
Moreover, the expression is not above criticism. In the first place, of course, it is negative: it expresses the idea that the grace of God whereby the elect are converted cannot be successfully resisted. But the truth is positive; and it is always better, if possible, to express that truth positively. In the second place, the expression itself is not above reproach. To speak of the power and operation of God’s grace as “irresistible” might leave the impression that the grace of salvation is such that the elect sinner is dragged kicking and screaming to heaven in spite of the fact that he resists and fights and pulls back all the way and does not want to be saved and does not want to believe and walk in godliness and sanctification of life. But this is exactly not the case. The Reformed doctrine of “irresistible grace” is actually a doctrine of effectual, or efficacious grace. This the Canons emphasize again and again. Article 10 of Canons III, IV speaks of the truth that God “confers upon them (the elect) faith and repentance, rescues them from the power of darkness, and translates them into the kingdom of His own Son. . . .” Article 11 speaks of the fact that God “powerfully illuminates their minds by His Holy Spirit” but also “by the efficacy of the same regenerating Spirit, pervades the inmost recesses of the man; He opens the closed, and softens the hardened heart, and circumcises that which was uncircumcised; infuses new qualities into the will, which though heretofore dead, He quickens; from being evil, disobedient, and refractory, He renders it good, obedient, and pliable; actuates and strengthens it, that like a good tree, it may bring forth the fruits of good actions.”
And Article 16 goes to the heart of the matter:
But indeed, even as through the fall man did not cease to be man, endowed with intellect and will, and neither did sin, which pervaded the whole human race, deprive him of the nature of mankind, but depraved and spiritually slew him, so also this divine grace of regeneration does not operate in men as in stocks and blocks, neither does it take away the will and its properties, or forcibly compel it against its will, but spiritually quickens, heals, corrects, powerfully and at the same time pleasantly turns it: so that where before the rebellion and opposition of the flesh had full dominion, now a ready and sincere obedience of the Spirit begins to reign—in which the true and spiritual renewal and liberty of our will consists. And unless that admirable Artificer of ever good deals in this wise with us, there is no hope that man should arise out of the fall through a free will, through which, when he stood, he plunged himself into ruin.
The relation between this Fourth Point and all the others is plain: it is one of perfect harmony. Irresistible grace is rooted in eternal and sovereign election. It has its ground in definite atonement: for all the blessings of salvation were merited and surely obtained by Christ for the elect, and for them alone. It has its spiritual necessity in a depravity which is indeed total, a depravity to which the only exception is the exception of efficacious grace. And it has its continuance and sure result in the preservation and perseverance of the saints.
Break that perfect harmony, and the inevitable result will be the loss of all of the Five Points of Calvinism.