As was said, it is important to consider that the literary contest of the church fathers with unbelief was carried on with: 1) the non-Christian Gentile world; 2) the non-Christian Jews; and 3) the heretics in the church. In this article attention is directed to the contest of the church with heresy. It was especially in this conflict that the substance of Christian truth was developed and its logical apprehension unfolded. For the assaults of heresy upon the truth, compelled the church to ponder its own articles of faith and oppose them, as fortified by the Scriptures, to the vain imaginings of the heretics. During the progress of this conflict, the church was led into the truth by Christ’s Spirit and empowered to exhibit the truth, clearly, logically, and with precision, in its symbols—the great creeds of Christendom.

Nearly all the fathers assailed the heresies of their day, the chief of which was gnosticism in its many forms. The weapons employed were the Scriptures and logic. The stand was that any system of thought, inwardly incoherent and anti-rational, must needs be a lie. The stand is correct. It always has been the stand of the church. The leading aim of the fathers was, of course, to establish the Christian truth on the firm basis of the Scriptures and to develop the truth.

One of the most revealing and precious remains of this type of early Christian literature is the work of Irenaeus Against Heresies. Little has come down to us of the personal history of this father. He was probably born in Syria, and removed, when still a lad, to Smyrna, or some neighboring city in Asia Minor. He himself tells us that in boyhood he was acquainted with Poly carp, the great and noble bishop of that city. He was thus born somewhere between A.D. 120 and A.D. 140. Certain it is that he was bishop of Lyons, in France, during the latter quarter of the second century. Though zealous for the truth, his zeal was tempered with the proper moderation. Victor, bishop of Rome, was enforcing uniformity throughout the church as to the observance of the pascal solemnities. Irenaeus warned him, in a letter, that, if he persisted in his harsh measures, the Catholic Church would be rent in pieces. The bishop allowed himself to be advised; and the controversy was waged less heatedly, until finally settled by the council of Nicea.

In his work Against Heresies Irenaeus, on the one hand, disproves and overthrows those multiform Gnostic heresies of the latter half of the second century; and, on the other hand, expounds and defends the Christian, i.e., Catholic faith. The work is divided into five boobs. The first of these sets forth and minutely describes the tenets of the numerous heretical sects. The description is interspersed with brief comments on their absurdity. In his second book, the author returns to those heresies and demolishes them through lengthy arguments, grounded principally on reason. The three remaining books exhibit the true doctrines of the Scriptures, as being utterly antagonistic to the views of the gnostic teachers. Following the author in that portion of his work, which is devoted to the exposition of Gnostic speculations, one stands amazed at the absurd theories of these heretics. It is doubtful whether anything more nonsensical than these could be imagined by rational beings. But the reader is also impressed by the deep piety, abhorrence of the lie, and love of the truth of our author.

He commences his treatise in this language: “Inasmuch as certain men have set the truth aside, and bring in lying words and vain genealogies, which, as the apostle says, ‘minister questions rather than godly edifying which is in faith,’ and by means of their craftily-constructed plausibility’s draw way the minds of the inexperienced and take them captive, I have felt constrained, my dear friend, to compose the following treatise in order to expose and counteract their machinations. These men falsify the oracles of God, and prove themselves evil interpreters of the good word of revelation. They also overthrow the faith of many, by drawing them away, under a pretense of superior knowledge, from Him who founded and adorned the universe; as if, forsooth, they had something more excellent and sublime to reveal to them, than that God, Who created heaven and earth, and all things that are therein,.

“Error, indeed, is never set forth in its naked deformity, lest, being thus exposed, it should at once be detected. But it is certainly decked out in an attractive dress, so as, by its outward form, to make it appear to the inexperienced (ridiculous as the expression may seem truer than the truth itself).

“I have deemed it my duty (after reading some of the commentaries, as they call them, of the disciples of Valentinus, and after making myself acquainted with their tenets through personal intercourse with some of them) to unfold to thee, my friend, these portentous and profound mysteries. . . .I do this, in order that thou mayest in turn explain them to all those with whom thou art connected, and exhort them to avoid such an abyss of madness and of blasphemy against Christ.”

That Gnosticism with its blasphemous irrationalities should have attracted so many adherents and proved itself a religious system to be exposed and not ignored shows to what depth of foolishness and moral corruption the human mind under heathenism had sunken, even when it professed knowledge and wisdom. “Professing themselves to be wise, they became fools” (Rom. 1:22). The task to which Irenaeus (and with him the fathers in general) addressed himself was twofold: (1) to show that the contrast of Gnosticism and Christianity was that of darkness and light, Christ and Belial, the temple of an idol and the temple of God, so that no one would henceforth confound the two; and (2) to so discredit the system that it could not survive. Irenaeus also achieved this objective. By the light of Heaven that flowed from him, and the other polemical writers, the fogs of gnosticism, that had risen from the abyss to obscure the truth, were dispelled and banished.

Irenaeus was a product of the Eastern church; but his field of labor was the West, He is the most sound representative of Christian doctrine of ‘these first three centuries. As his polemic was directed against Gnosticism, he expounds and vindicates the doctrines of the oneness of God, the creation of the world, the incarnation of the Son of God, His true humanity and true divinity. Against the antinomianism of heresy, he proves the oneness of the Old and New Testaments. He closes his work with treatises on the resurrection of the body, the antichrist, the end of the world, the intermediate state, and the millennium.

Another church father who came out against the contemporary heresies is Turtullian, whose full name was Quintus Septimus Florans Tertullianus. He is rated as the greatest of the ancient church writers of the West with the exception of Augustine, as a man of great originality and genius, characterized by deepeth pathos, the liveliest fancy, and the most penetrating keenness.

Born a heathen, he became a Christian in mature manhood, although this is not certain. He was a native of the province of Africa (the present Tunisia) and the city of Carthage. He was the son of a proconsular centurion. His birth is assigned to A.D. 145 and he is said to have reached a very advanced age. He was a presbyter in the church and married. In his second epistle to his wife, he pays a glowing tribute to the Christian marriage state. “What kind of yoke,” he wrote, “is that of two believers, partakers of one hope, one desire? Both are brethren, both fellow servants, no difference of spirit or of flesh; nay, they are truly “two in one flesh.” Where the flesh is one, one is the spirit too. Together they pray, together prostrate themselves, together perform their fasts; mutually teaching, mutually exhorting, mutually sustaining. Equally are they both found in the church of God; equally at the banquet of God; equally in straits, in persecution, in refreshments. Neither hides ought from the other; neither shuns the other; neither is troublesome to the other. The sick is visited, the indigent relieved, with freedom. Alms are given without danger of ensuing torments; sacrifice attended without scruple; daily diligence discharged without impediment: Between the two echo psalms and hymns; and they mutually challenge each other which shall better chant to the Lord. Such things when Christ sees and hears, He joys. To these He sends His own peace. Where two are, there is He Himself. Where He is, there the evil one is not.”

Tertullian received an excellent education in Latin and in Greek and was able to speak and write both. He was familiar with the old historians, had at his command the writings of the Greek philosophers, was accurately acquainted with Roman law, which he also practiced at Rome before his conversion. As a jurist he enjoyed the reputation of being one of the most eminent. After his conversion he gave himself with all his colossal energy to the study of the Scriptures and of Christian literature, whose content he mastered. For what he did, he did with his whole being. Once a Christian, he was so with his whole soul. He was a foe of all half measures and compromises with the world. For the culture of the world he had only contempt. He scorned the Grecian philosophers as ‘the fathers of all heresies. “These are”, wrote he, “the doctrines of men and of demons (to wit, the heresies), produced for itching ears of the spirit of this world’s wisdom: this the Lord called foolishness and chose the foolish things of the world to confound even philosophy itself. For philosophy’ it is which is the material of the world’s wisdom, the rash interpreter of the nature and the dispensation of God. Indeed heresies themselves are instigated by philosophy” (On Prescription Against Heresies).

Tertullian was a man of strong passion and vehement temper. With his opponents, whoever they were, heathen, Jews, heretics, Catholics, he had little patience. In this respect he was like Luther. In the language of one historian: “With the adroitness of a special pleader he entangled them in self-contradictions, pursued them into every nook and corner, overwhelmed them with arguments and sarcasms, drove them before him with unmerciful lashings, and almost always made them ridiculous and contemptible.” It is a wonder that he was not killed by the heathen. In attacking the formidable heretic Marcion, he literally exhausted his vocabulary of abuse. He sets out with describing Pontus, the native province of Marcion, as a land unfit for human habitation on account of its physical and climatic abnormities, and the people who dwelt there as an inhuman race of men, and then goes on to say: “Nothing in Pontus is so barbarous and sad as the fact that Marcion was born there, fouler than any seythian, more roving than the Samatian, more inhuman than the Massagate, more audacious than an Amazon, darker than the cloud of the Euxine, colder than its winter, more brittle than its ice, more deceitful than the Ister, more craggy than the Caucasus. Nay, more, the Almighty God is mangled by Marcion’s blasphemies. Marcion is more savage than even the beasts of that barbarous region. For what Beaver was ever a greater emasculator than he who has abolished the nuptial bond? What Pontias mouse had such gnawing powers as he who has gnawed the gospel to pieces.”

This retort, however violent, is deserved. Marcion’s doctrines did truly “gnaw the gospels in pieces,” assailing the sacred Scriptures by distortions and corruptions of the text itself, and forming the most daring blasphemies against Him who is proclaimed God by the law and the prophets and against Christ.

Tertullian had a tendency to run into extremes, better said, heretical notions. As he advanced in years, this tendency took on strength and drove him, when he was about fifty years old, into leaving the Catholic church and joining himself to the sect of the Montanists. To what degree this lapse of his was lamentable is a matter for debate. Montanism, in its doctrines, agreed in all the essential points with the Catholic church. It held firmly to the traditional rule of faith. But it was characterized by a fanatical zeal in church discipline, by a belief in the continuance of the charismatic gifts of the apostolic church and the free working of the spirit and by opposition to the fixed order of ecclesiastical organization. It also looked for Christ’s speedy return to earth to reign during the millennium. What attracted Tertullian to this sect was its contempt of the world, its asceticism, and moral sternness. Tertullian the Montanist severely criticized the Catholics, whom he called psychics. In the ethical writings, which he put forth during the period of his lapse, he decries their growing worldliness and lax discipline. But, as a censure of morals, he was disqualified by the Monatist in him. “I should wonder at the Psychics,” so reads the first few lines of his treatise on Fasting, “if they were enthrawled to voluptousness alone, which leads them into repeated marriages, if they were not likewise bursting with gluttony, which leads them to hate fasts.” In this treatise he justified the extremes of the Montanist fast, and thereby forged it into a weapon for a cruel attack upon the brethren. In his second epistle to his wife, he pays beautiful tribute to the Christian marriage state, blessed by the church and an object of joy to Christ, But in his treatise on Molnogamy, written during the period of his lapse, he fanatically would make out that second marriage is but refined adultery.

After having done battle with heathen, Jews, Marcionites, Gnostics, Monarchians and Catholics—his whole life was spent in an atmosphere of strife—he died an old man. In appraising this remarkable man and his works, we must distinguish between Tertullian the Catholic and Tertullian the Montanist. As to the heart of his dispositions, he remained all his life Tertullian the Catholic and as such an ardent advocate and powerful defender of the Catholic faith. And to this faith he rendered invaluable services. From him sprang full grown, Latin Christian literature. He introduced the modes of thought and supplied the terms that made the Latin tongue capable of expressing the mind of the church in the great Trinitarian and Christological controversies of subsequent centuries. He was the first to suppose a distinction in God Himself. In his polemic “Against Praxeas” he anticipates the Nicene doctrine of the blessed Trinity. “As if,” says he, “in this way also One were not all and that All are of One, by unity (that is) of substance; while the mystery of the Dispensation is still guarded, which distributes the Unity into a Trinity, placing in their order the three Persons—the Father, the Son, and the Holy Ghost: three, however, not in condition, but in degree; not in substance, but in form; not in power, but in aspect (specie); yet of one substance, and of one condition (statu), and of one power, inasmuch as He in One God, from whom these degrees and forms and aspects are reckoned, under the name of the Father, and of the Son, and of the Holy Ghost.”

Tertullain glorified the Scriptures as the sole rule of faith. His quotations are numerous and their uses penetrating. His ethical writings are characterized by a lively conception of sin; he thus opened the way for the doctrine of man, as afterwards developed by Augustine. Finally, in tracking down and defeating the gnostic Marcion, the most dangerous among the heretics, he performed a work of inestimable worth for the Christian faith. But his theology is marred by defective speculative opinions.

Of not one of the fathers of this period can it be said that they did not mix truth with error. This can be explained. The church had just crossed the threshold of the New Testament Dispensation. The study of the Scriptures, the mastication and digestion of its contents, had barely begun. Then, too, most of the fathers of the second century were soldiers of Christ, recruited not, as the apostles, from the Old Testament church, and not, as the Reformers, from the Roman Catholic church, but from heathendom. Though filled with courage and enthusiasm for the new faith, they did not wholly succeed in freeing themselves from the influence of paganism, in cleansing their soul from its vain wisdom and habits of thought. (For that matter, theologians in general to this very day haven’t succeeded in this.) This is especially true of the Greek fathers of this period, in particular of Origen and the school which he represented. His striving seems to have been to unite in one grand and massive thought-structure the wisdom of man on the one hand, and the wisdom of God, on the other.

The fathers of those first three centuries gave to the church no systematic theology. Yet, in the mass of Christian literature, which they jointly produced in their contact with unbelief, and, in particular, with heresy, is found the embryo of all the later dogmas: God and creation; Man and the fall; Christ, His incarnation, essential divinity, and true humanity; the Holy Trinity; the Holy Spirit, His personality etc.

(In their struggle with heresy, the efforts of the fathers were concerned, principally, with establishing the doctrines of the rule of faith, especially the Holy Trinity, the incarnation of God and the true divinity and the true humanity of Christ. In this effort, the church was led unerringly by the Spirit and the word in the way of right thinking, between the threatening cliffs. But the representations of these doctrines are, in this period, characterized by no little obscurity and indefiniteness. Expressions occur which were studiously avoided in aftertimes. Thus Tertullian calls the Father the whole substance and the Son a derivation and portion of the whole,. Many clear testimonies can be adduced to prove that he taught the eternity of the Logos. But he also teaches that the Son of God was made and was called the Word at the time He went out from God the Father with the voice, “Let there be light” (From his treatise Against Praxreas).

The excellencies of the fathers of the first three centuries varies especially with respect to the stand they took against pagan philosophy. It was wholeheartedly repudiated by the Latin fathers, while the Greek fathers viewed it as to an extent a gift of God and a schoolmaster for Christ, like the law in the sphere of religion.

As was said, the number of Polemical works, treatises against heresies, of these fathers that have come down to us is not large. Besides those already referred to, there are but a few more to be mentioned. Most of them were put out in refutation of the multiform gnostic heresies, the primary principles of which have been stated in a previous article; some of them in refutation of antitrinitarian heretics, known as monarchians or Unitarians, and who taught that God is one in person as well as in being. If the controversies with the gnostic heresies occupied the whole second century, the controversy with the Unitarians filled the whole third.