This is long, but worth your time, I think. John Owen writing on Matthew 16:18 in his preface to The Glory of Christ, shows it is Christ's church, not men, councils, or assemblies, that is the pillar and ground of truth.
The interesting point he makes is that before the universal church was a practice, heresies came and went but didn't make great headway. It wasn't until the universal church and councils tried to "nail down" and define truth, that heresies grew. These "church councils" then did more harm than good. When men try to improve upon a divine institution, by dividing or taking away, they make it worse.
Think how much error and division has come from groups like The Gospel Coalition or any number of "ministries" ran by celebrity pastors and book sellers. Though they have published many good things, the harm they have done outstrips the good.
"The defense of the truth, from the beginning, was left in charge unto, and managed by, the guides and rulers of the church in their several capacities. And by the Scripture it was that they discharged their duty, confirmed with apostolical tradition consonant thereunto. This was left in charge unto them by the great apostle, (Acts xx. 28–31; 1 Tim. vi. 13, 14; 2 Tim. ii. 1, 2, 15, 23, 24, iv. 1-5,) and wherein any of them failed in this duty, they were reproved by Christ himself: Rev. ii. 14, 15, 20. Nor were private believers (in their places and capacities) either unable for this duty or exempt from it, but discharged themselves faithfully therein, according unto commandment given unto them: 1 John ii. 20, 27, iv. 1-3; 2 John 8, 9. All true believers, in their several stations—by mutual watchfulness, preaching, or writing, according unto their calls and abilities—effectually used the outward means for the preservation and propagation of the faith of the church. And the same means are still sufficient unto the same ends, were they attended unto with conscience and diligence. The pretended defence of truth with arts and arms of another kind hath been the bane of religion, and lost the peace of Christians beyond recovery. And it may be observed, that whilst this way alone for the preservation of the truth was insisted on and pursued, although innumerable heresies arose one after another, and sometimes many together, yet they never made any great progress, nor arrived unto any such consistency as to make a stated opposition unto the truth; but the errors themselves, and their authors, were as vagrant meteors, which appeared for a little while, and vanished away. Afterwards it was not so, when other ways and means for the suppression of heresies were judged convenient and needful.
For in process of time, when the power of the Roman empire gave countenance and protection unto the Christian religion, another way was fixed on for this end, viz., the use of such assemblies of bishops and others as they called General Councils, armed with a mixed power, partly civil and partly ecclesiastical—with respect unto the authority of the emperors and that jurisdiction in the church which began then to be first talked of. This way was begun in the Council of Nice, wherein, although there was a determination of the doctrine concerning the person of Christ—then in agitation, and opposed, as unto his divine nature therein-according unto the truth, yet sundry evils and inconveniences ensued thereon. For thenceforth the faith of Christians began greatly to be resolved into the authority of men, and as much, if not more weight to be laid on what was decreed by the fathers there assembled, than on what was clearly taught in the Scriptures. Besides, being necessitated, as they thought, to explain their conceptions of the divine nature of Christ in words either not used in the Scripture, or whose significa-, tion unto that purpose was not determined therein, occasion was given unto endless contentions about them. The Grecians themselves could not for a long season agree among themselves whether oủsia and iTÓCTCOIS were of the same signification or no, (both of them denoting essence and substance,) or whether they differed in their signification, or if they did, wherein that difference lay. Athanasius at first affirmed them to be the same: Orat. v. con. Arian., and Epist. ad African Basil denied them so to be, or that they were used unto the same purpose in the Council of Nice: Epist. lxxviii. The like difference immediately fell out between the Grecians and Latins about “hypostasis” and “persona.” For the Latins rendered “hypostasis” by “substantia," and mpóOWTOV by “ persona.” Hereof Jerome complains, in his Epistle to Damasus, that they required of him in the East to confess“ tres hypostases,” and he would only acknowledge“ tres personas:" Epist. lxxi. And Augustine gives an account of the same difference: De Trinitate, lib. v. cap. 8, 9. Athanasius endeavoured the composing of this difference, and in a good measure effected it, as Gregory Nazianzen affirms in his oration concerning his praise. It was done by him in a synod at Alexandria, in the first year of Julian's reign. On this occasion many contests arose even among them who all pleaded their adhe. rence unto the doctrine of the Council of Nice. And as the subtle Arians made incredible advantage hereof at first, pretending that they opposed not the deity of Christ, but only the expression of it by ouoouolos, so afterwards they countenanced themselves in coining words and terms, to express their minds with, which utterly rejected it. Hence were their oworoccios, ¿Tepovolos, oủx övrwv, and the like names of blasphemy, about which the contests were fierce and endless. And there were yet farther evils that ensued hereon. For the curious and serpentine wits of men, finding themselves by this means set at liberty to think and discourse of those mysteries of the blessed Trinity, and the person of Christ, without much regard unto plain divine testimonies, (in such ways wherein cunning and sophistry did much bear sway,) began to multiply such new, curious, and false notions about them, especially about the latter, as caused new disturbances, and those of large extent and long continuance. For their suppression, councils were called on the neck of one another, whereon commonly new occasions of differences did arise, and most of them managed with great scandal unto the Christian religion. For men began much to forego the primitive ways of opposing errors and extinguishing heresies; betaking themselves unto their interest, the number of their party, and their prevalency with the present emperors. And although it so fell out--as in that at Constantinople, the first at Ephesus, and that at Chalcedon--that the truth (for the substance of it) did prevail, (for in many others it happened quite otherwise,) yet did they always give occasions unto new divisions, animosities, and even mutual hatreds, among the principal leaders of the Christian people. And great contests there were among some of those who pretended to believe the same truth, whether such or such a council should be received—that is, plainly, whether the church should resolve its faith into their authority. The strifes of this nature about the first Ephesian Council, and that at Chalcedon, not to mention those wherein the Arians prevailed, take up a good part of the ecclesiastical story of those days. And it cannot be denied, but that some of the principal persons and assemblies who adhered unto the truth did, in the heat of opposition unto the heresies of other men, fall into unjustifiable excess themselves.
We may take an instance hereof with respect unto the Nestorian heresy, condemned in the first Ephesian Council, and afterward in that at Chalcedon. Cyril of Alexandria, a man learned and vehement, designed by all means to be unto it what his predecessor Athanasius had been to the Arian; but he fell into such excesses in ķis undertakings, as gave great occasion unto farther tumults. For it is evident that he distinguisheth not between υπόστασις and φύσις, and therefore affirms, that the divine Word and humanity had uicer qúorv, one nature only. So he doth plainly in Epist. ad Successum : “ They are ignorant,” saith he, őri nat' årýderav goti uía púois toũ hóyou GEOAprouévn. Hence Eutyches the Archimandrite took occasion to run into a contrary extreme, being a no less fierce enemy to Nestorius than Cyril was. For to oppose him who divided the person of Christ into two, he confounded his natures into one—his delirant folly being confirmed by that goodly assembly, the second at Ephesus. Besides, it is confessed that Cyril—through the vehemency of his spirit, hatred unto Nestorius, and following the conduct of his own mind in nice and subtle expressions of the great mystery of the person of Christ-did utter many things exceeding the bounds of sobriety prescribed unto us by the apostle, (Rom. xii. 3,) if not those of truth itself. Hence it is come to pass, that many learned men begin to think and write that Cyril was in the wrong, and Nestorius by his means condemned undeservedly. However, it is certain to me, that the doctrine condemned at Ephesus and Chalcedon as the doctrine of Nestorius, was destructive of the true person of Christ; and that Cyril, though he missed it in sundry expressions, yet aimed at the declaration and confirmation of the truth; as he was long since vindicated by Theorianus: Dialog. con. Armenios.
However, such was the watchful care of Christ over the church, as unto the preservation of this sacred, fundamental truth, concerning his divine person, and the union of his natures therein, retaining their distinct properties and operations, that—notwithstanding all the faction and disorder that were in those primitive councils, and the scandalous contests of many of the members of them; notwithstanding the determination contrary unto it in great and numerous councils—the faith of it was preserved entire in the hearts of all that truly believed, and triumphed over the gates of hell.
I have mentioned these few things, which belong unto the promise and prediction of our blessed Saviour in Matthew 16:18, (the place insisted on,) to show that the church, without any disadvantage to the truth, may be preserved without such general assemblies, which, in the following ages, proved the most pernicious engines for the corruption of the faith, worship, and manners of it. Yea, from the beginning, they were so far from being the only way of preserving truth, that it was almost constantly prejudiced by the addition of their authority unto the confirmation of it. Nor was there any one of them wherein “ the mystery of iniquity” did not work, unto the laying of some rubbish in the foundation of that fatal apostasy which afterwards openly ensued. The Lord Christ himself hath taken it upon him to build his church on this rock of his person, by true faith of it and in it. He sends his Holy Spirit to bear testimony unto him, in all the blessed effects of his power and grace. He continueth his Word, with the faithful ministry of it, to reveal, declare, make known, and vindicate his sacred truth, unto the conviction of gainsayers. He keeps up that faith in him, that love unto him, in the hearts of all his elect, as shall not be prevailed against. Wherefore, although the oppositions unto this sacred truth, this fundamental article of the church and the Christian religion—concerning his divine person, its constitution, and use, as the human nature conjoined substantially unto it, and subsisting in it-are in this last age increased; although they are managed under so great a variety of forms, as that they are not reducible unto any heads of order; although they are promoted with more subtlety and specious pretences than in former ages; yet, if we are not wanting unto our duty, with the aids of grace proposed unto us, we shall finally triumph in this cause, and transmit this sacred truth inviolate unto them that succeed us in the profession of it."
