1 Now all these [heretics] are of much later date than the bishops to whom the apostles committed the Churches; which fact I have in the third book taken all pains to demonstrate. It follows, then, as a matter of course, that these heretics aforementioned, since they are blind to the truth, and deviate from the [right] way, will walk in various roads; and therefore the footsteps of their doctrine are scattered here and there without agreement or connection. But the path of those belonging to the Church circumscribes the whole world, as possessing the sure tradition from the apostles, and gives unto us to see that the faith of all is one and the same, since all receive one and the same God the Father, and believe in the same dispensation regarding the incarnation of the Son of God, and are cognizant of the same gift of the Spirit, and are conversant with the same commandments, and preserve the same form of ecclesiastical constitution, and expect the same advent of the Lord, and await the same salvation of the complete man, that is, of the soul and body. And undoubtedly the preaching of the Church is true and steadfast, in which one and the same way of salvation is shown throughout the whole world. For to her is entrusted the light of God; and therefore the “wisdom” of God, by means of which she saves all men, “is declared in [its] going forth; it utters [its voice] faithfully in the streets, is preached on the tops of the walls, and speaks continually in the gates of the city.” For the Church preaches the truth everywhere, and she is the seven-branched candlestick which bears the light of Christ.
2. Those, therefore, who desert the preaching of the Church, call in question the knowledge of the holy presbyters, not taking into consideration of how much greater consequence is a religious man, even in a private station, than a blasphemous and impudent sophist. Now, such are all the heretics, and those who imagine that they have hit upon something more beyond the truth, so that by following those things already mentioned, proceeding on their way variously, inharmoniously, and foolishly, not keeping always to the same opinions with regard to the same things, as blind men are led by the blind, they shall deservedly fall into the ditch of ignorance lying in their path, ever seeking and never finding out the truth. It behooves us, therefore, to avoid their doctrines, and to take careful heed lest we suffer any injury from them; but to flee to the Church, and be brought up in her bosom, and be nourished with the Lord's Scriptures. For the Church has been planted as a garden (paradisus) in this world; therefore says the Spirit of God, “You may freely eat from every tree of the garden,” that is, Eat from every Scripture of the Lord; but you shall not eat with an uplifted mind, nor touch any heretical discord. For these men do profess that they have themselves the knowledge of good and evil; and they set their own impious minds above the God who made them. They therefore form opinions on what is beyond the limits of the understanding. For this cause also the apostle says, “Be not wise beyond what it is fitting to be wise, but be wise prudently,” that we be not cast forth by eating of the “knowledge” of these men (that knowledge which knows more than it should do) from the paradise of life. Into this paradise the Lord has introduced those who obey His call, “summing up in Himself all things which are in heaven, and which are on earth;” but the things in heaven are spiritual, while those on earth constitute the dispensation in human nature (secundum hominem est dispositio). These things, therefore, He recapitulated in Himself: by uniting man to the Spirit, and causing the Spirit to dwell in man, He is Himself made the head of the Spirit, and gives the Spirit to be the head of man: for through Him (the Spirit) we see, and hear, and speak.
Source: Adversus haereses (New Advent)