Guarding against Wavering

It is good divinity to maintain that scepticism, fluctuation and wavering, concerning those things which God hath revealed to be believed or done by us, is a sin; and to be firm, fixed and established in the faith, is a duty commanded. I shall first prove it to be so; then give reasons for it; and, thirdly, some helps to this duty, and preservatives against this sin.

For proof of the thing, somewhat might be said from the very light of nature; for "hath a nation changed their gods?" Jer. 2.11...But, to set aside nature's light, there is not any of the primitive churches to which the apostles wrote epistles, but they were expressly warned, either positively, to stand fast in the faith, to hold fast their profession, or, negatively, to beware of, and to avoid false teachers, and not to be carried about with divers and strange doctrines. Now it must needs be not only a truth, but a most special and necessary truth, which the apostles thought fit thus to press upon the churches in all their epistles written to them. See Rom. 16.17,18; 1 Cor. 16.13; 2 Cor. 11.3,4; Gal. 1.6,8; Eph. 4.14; Phil. 3.2,18; Col. 2.6-8; 2 Thess. 2.2,3; Heb. 10.23; 13.9; James 5.19,20; 2 Pet. 2.1-3; 3.16-18; 1 John 4. 1; Jude 3,4. All these texts are full and plain as to this point which I speak to, and in that respect most worthy of our frequent thoughts and observation, especially at such a time when this corner of the world is so full of new and strange doctrines.

As for the reasons, take these:
1. If we be not steadfast and immovable in the profession of our faith, we frustrate (as to us) the end for which the Scriptures were written. Luke gives this reason to his Theophilus why he wrote the story of Christ's birth, life and death, "That thou mightest know the certainty of those things wherein thou hast been instructed," Luke 1.4. When Peter hath mentioned the voice which came from heaven concerning Christ, he addeth the certainty of the Scripture as a greater certainty, "We have also a more sure word of prophesy, whereunto ye do well that ye take heed, as unto a light that shineth in a dark place," 2 Pet. 1.19. A voice from heaven might sooner deceive us than the written word of God.
2. To maintain and profess the true doctrine, and the true faith, is, by all protestant orthodox writers, made one, yea, the principal mark of a true visible church. Christ himself, John x. 4, 5, gives us this mark of his sheep, "The sheep follow him (their shepherd), for they know his voice, and a stranger will they not follow, for they know not the voice of strangers."
3. If once we forsake the way of truth, and go into an erroneous way, we shall not know where to find our paths, we shall wander from mountain to hill, and forget our resting place. As one wave comes after another, so doth one error come after another. As a canker spreadeth, so doth error, 2 Tim. 2.19; "Evil men and seducers shall wax worse and worse, deceiving and being deceived," 2 Tim. 3.13: which hath made some, and I hope will make more, who were too inclinable to the new doctrine and practices of sectaries at first, now to fall off from them, when "they increase unto more ungodliness," and unto more error. And there is no end; one error breedeth a hundred, and a hundred will breed ten thousand. What was it that made so many fall off from the prelates who once joined with them? Was it not because they were growing from the old ceremonies to many new ones, and each year, almost, brought in some new superstition, and from popish rites they grew to popish doctrines?
4. If we waver and be led about with divers and strange doctrines, then the prophecies which have gone before of the true church shall not be made good in us. It was promised concerning the church and kingdom of Christ, Isa. 32.4,5, "The heart also of the rash shall understand knowledge, and the tongue of the stammerers shall be ready to speak plainly, the vile person shall no more be called liberal," &c., that is, those who simply and rashly were led about with every wind of doctrine shall be so wise and knowing as to distinguish between truth and error, between virtue and vice, and call each thing by its right name. So Isa. 33. 6, "And wisdom and knowledge shall be the stability of thy times, and strength of salvation."
5. Instability and forsaking the way of truth makes us lose much that we had gained, 2 John 8; all the comfort we enjoyed, all the good that ever our souls received of such a truth, such a cause, such a ministry, all that ever we did, or spake, or suffered for the truth, all this we lose when we turn aside after an erroneous way. 6. It greatly hindereth our spiritual comfort and contentment. Col. 2.2, to be knit together in love is one mean, and to have all riches of the full assurance of understanding to the acknowledgment of gospel truths, is another mean by which the Apostle wisheth the hearts of Christians to be comforted. It added much to Paul's comfort that he could say, "I have kept the faith, henceforth there is laid up for me a crown," &c., 2 Tim. 4.7,8.
7. We run a great hazard of our souls and our salvation when we turn aside from truth to error. It is said of the unstable, that they wrest the Scriptures "unto their own destruction," 2 Pet. 3.16. Like a man fallen into quicksands, the more he wrestles out the more he sinks. When the Apostle hath spoken of Christ's purchasing of our reconciliation, justification and sanctification, he addeth an if; Col. 1.23, "If ye continue in the faith grounded and settled, and be not moved away from the hope of the gospel, which ye have heard." Not that our persevering in the true faith was a condition in Christ's purchasing of these blessings, but it is a condition without which we cannot possess and enjoy what Christ hath purchased; that is, he that falls away from the true doctrine of the gospel, proves himself to have no part of the benefits of Christ.

Some errors are, in their own nature, damnable and inconsistent with the state of grace or a fellowship with God, 2 Peter 2. 9; so 2 John 9, "Whosoever transgresseth and abideth not in the doctrine of Christ, hath not God." Sure it may be said of Arians, Socinians, Papists, Libertines, they have not God, because they abide not in the doctrine of Christ; so Gal. 5.4. Other errors there are, of which I may say, whatsoever they are comparatively, impenitency, and continuing in them, doth condemn, whence it is that the apostle James reckoneth him who errs from the truth to be in a way of death and danger of damnation, James 5.19,20.

Now, the preservatives against wavering, and helps to stedfastness in the faith, are these:
1. Grow in knowledge and circumspection; be not simple as children in understanding. There is "a sleight of men, and cunning craftiness, whereby they lie in wait to deceive;" so speaks the Apostle of those that spread divers and strange doctrines, Eph. 4.14; and Rom. 16.18, he warns us that they do "by good words and fair speeches, deceive the hearts of the simple." Thou hast, therefore, need of the wisdom of the serpent, that thou be not deceived, as well as of the simplicity of the dove, that thou be not a deceiver, Phil. 1. 9,10. Do not rashly engage into any new opinion, much less into the spreading of it. With the well-advised is wisdom. Pythagoras would have his scholars only to hear, and not to speak for five years. Be swift to hear, but not to speak or engage: "Prove all things," and when thou hast proved, then be sure to "hold fast that which is good," 1 Thess. 5.21; Matt. 7.15,17. There was never an heresy yet broached, but under some fair plausible pretence: "beguiling unstable souls," as Peter speaks, 2 Peter 2.14. Prov. 14.15, "The simple believeth every word. Be not like the two hundred that "went in the simplicity of their hearts" after Absalom in his rebellion, not knowing anything, but that he was to pay his vow in Hebron, 2 Sam. 15.11.
2. Grow in grace and holiness, and the love of the truth; for the stability of the mind in the truth, and the stability of the heart in grace, go hand in hand together, Heb. 13. 9. David's rule is good: Psal. 25.12, "What man is he that feareth the Lord? him shall ye teach in the way that he shall choose;" which is also Christ's rule, John 7.17, "If any man will do his will, he shall know of the doctrine, whether it be of God, or whether I speak of myself;" see also Deut. 11.13,16. Elisha healed the unwholesome waters of Jericho by casting salt into the fountain, 2 Kings 2.21. So must the bitter streams of pernicious errors be healed by getting the salt of mortification and true sanctifying grace in the fountain.
3. Be sure to cleave to thy faithful and sound teachers. The sheep that follow the shepherd are best kept from the wolf. I find the exhortation to stability in the faith joined with the fruitful labours of faithful teachers, Phil. 3.16,17; Heb. 13.7,9. So the Apostle, Eph. 4.11-14, from the work of the ministry draweth this consequence, "That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine." The Galatians were easily seduced, as soon as they were made to disgust Paul.
4. Watch and be vigilant against the first beginnings of declining, against the first seeds of error, Gal. 5.9. It was "while men slept" that the enemy came and sowed tares among the wheat, and when he had done, went his way, Matt. 13.25. Therefore "watch ye, stand fast in the faith," 1 Cor. 16.12; go hand in hand together.
5. Avoid and withdraw from the authors and spreaders of heresies and dangerous errors, Rom. 16.17; 1 Tim. 6.5; 2 John 10,11; Phil. 3.2. He that would be godly should not use ungodly company, and he that would be orthodox should not use heretical company, unless he have some good hopes to convert some who have erred from the truth, and come into their company only for that end, James 5.19,20. I remember Chrysostom, in divers places, warneth his hearers how much they endangered their souls by going into the Jewish synagogues, and there was a great zeal in the ancient church to keep Christians that were orthodox from the assemblies and company of heretics.
6. Get church discipline established and duly exercised, which is ordained to purge the church from false doctrine, Rev. 2.14,20.
7. "Lean not unto thine own understanding," and "be not wise in thine own eyes," Prov. 3.5,7. Let reason be brought into captivity to the obedience of Christ, 2 Cor. 10.5. That which made the Antitrinitarians and Socinians fall away from the belief of the trinity of persons in the Godhead, and of the union of the two natures of God and man in the person of Christ, was, because their reason could not comprehend these articles, which is the ground of their opinion professed by themselves. When I speak of captivating reason, I do not mean implicit faith. The eyes of my understanding must be so far opened by the Holy Ghost, that I may know such an article is held forth in Scripture to be believed, and therefore I do believe that it is, though my reason cannot comprehend how it is.
8. Count thy cost, and be well resolved beforehand what it will cost thee to be a disciple of Christ, to be a constant professor of the truth, Luke 14.26-34; Acts 14.22, "Confirming the souls of the disciples, and exhorting them to continue in the faith, and that we must through much tribulation enter into the kingdom of God." This is surer than to confirm ourselves with the hopes of a golden age of prosperity, in which we shall feel no affliction.
9. "Search the Scriptures," John 5.39; Acts 17.11. Do not take upon trust new lights from any man, be he never so eminent for parts or for grace, but to the law and the testimony.

The upshot of all is, that we ought to hold fast the profession of our faith without wavering, and be steadfast, and even immovable in the truth, and not to give place to the adversaries, no, not for an hour, Gal. 2.4,5. I do not mean pertinacy in the least error, nor a vain presumptuous overweening conceit of our knowledge, to make us despise any light which others may give us from Scripture. Pertinacy is an evil upon the one hand, and to be too tenacious of our own opinions; but that...that levity, inconstancy, wavering, scepticism, is an evil upon the other hand. 2 Thess. 2.2, "Be not soon shaken in mind." &c.

Of Stability and Firmness in the Truth, from Miscellany Questions by George Gillespie.