Christ Jesus our Lord (may He bear with me a moment in thus expressing myself!), whosoever He is, of what God soever He is the Son, of what substance soever He is man and God, of what faith soever He is the, teacher, of what reward soever He is the Promiser, did, whilst He lived on earth, Himself declare what He was, what He had been, what the Father’s will was which He was administering, what the duty of man was which He was prescribing; (and this declaration He made,) either openly to the people, or privately to His disciples, of whom He had chosen the twelve chief ones to be at His side, (Mar_4:34) and whom He destined to be the teachers of the nations. Accordingly, after one of these had been struck off, He commanded the eleven others, on His departure to the Father, to “go and teach all nations, who were to be baptized into the Father, and into the Son, and into the Holy Ghost.” (Mat_28:19) Immediately, therefore, so did the apostles, whom this designation indicates as “the sent.” Having, on the authority of a prophecy, which occurs in a psalm of David, (Psa_109:8; compare Act_1:15-20) chosen Matthias by lot as the twelfth, into the place of Judas, they obtained the promised power of the Holy Ghost for the gift of miracles and of utterance; and after first bearing witness to the faith in Jesus Christ throughout Judaea, and rounding churches (there), they next went forth into the world and preached the same doctrine of the same faith to the nations. They then in like manner rounded churches in every city, from which all the other churches, one after another, derived the tradition of the faith, and the seeds of doctrine, and are every day deriving them, that they may become churches. Indeed, it is on this account only that they will be able to deem themselves apostolic, as being the offspring of apostolic churches. Every sort of thing must necessarily revert to its original for its classification. Therefore the churches, although they are so many and so great, comprise but the one primitive church, (rounded) by the apostles, from which they all (spring). In this way all are primitive, and all are apostolic, whilst they are all proved to be one, in (unbroken) unity, by their peaceful communion, and title of brotherhood, and bond of hospitality, – privileges which no other rule directs than the one tradition of the selfsame mystery.
XXI. – All Doctrine True Which Comes Through the Church from the Apostles, who Were Taught by God Through Christ. All Opinion Which Has No Such Divine Origin and Apostolic Tradition to Show, Is Ipso Facto False.
From this, therefore, do we draw up our rule. Since the Lord Jesus Christ sent the apostles to preach, (our rule is) that no others ought to be received as preachers than those whom Christ appointed; for “no man knoweth the Father save the Son, and he to whomsoever the Son will reveal Him.” (Mat_11:27) Nor does the Son seem to have revealed Him to any other than the apostles, whom He sent forth to preach – that, of course, which He revealed to them. Now, what that was which they preached – in other words, what it was which Christ revealed to them – can, as I must here likewise prescribe, properly be proved in no other way than by those very churches which the apostles rounded in person, by declaring the gospel to them directly themselves, both rivet race, as the phrase is, and subsequently by their epistles. If, then, these things are so, it is in the same degree manifest that all doctrine which agrees with the apostolic churches – those molds and original sources of the faith must be reckoned for truth, as undoubtedly containing that which the (said) churches received from the apostles, the apostles from Christ, Christ from God. Whereas all doctrine must be prejudged as false which savors of contrariety to the truth of the churches and apostles of Christ and God. It remains, then, that we demonstrate whether this doctrine of ours, of which we have now given the rule, has its origin in the tradition of the apostles, and whether all other doctrines do not ipso facto proceed from falsehood. We hold communion with the apostolic churches because our doctrine is in no respect different from theirs. This is our witness of truth.
~Tertullian- Against Heresies Vol. 3