Peter and Paul were martyred in Rome

We read the lives of the Cæsars: At Rome Nero was the first who stained with blood the rising faith. Then is Peter girt by another, when he is made fast to the cross. Then does Paul obtain a birth suited to Roman citizenship, when in Rome he springs to life again ennobled by martyrdom.  Wherever I read of these occurrences, so soon as I do so, I learn to suffer; nor does it signify to me which I follow as teachers of martyrdom, whether the declarations or the deaths of the apostles, save that in their deaths I recall their declarations also.

Tertullian
Scorpiace
Chapter XV

A summation of the orthodox faith

We, however, as we indeed always have done (and more especially since we have been better instructed by the Paraclete, who leads men indeed into all truth), believe that there is one only God, but under the following dispensation, or οἰκονομία , as it is called, that this one only God has also a Son, His Word, who proceeded from Himself, by whom all things were made, and without whom nothing was made. Him we believe to have been sent by the Father into the Virgin, and to have been born of her—being both Man and God, the Son of Man and the Son of God, and to have been called by the name of Jesus Christ; we believe Him to have suffered, died, and been buried, according to the Scriptures, and, after He had been raised again by the Father and taken back to heaven, to be sitting at the right hand of the Father, and that He will come to judge the quick and the dead; who sent also from heaven from the Father, according to His own promise, the Holy Ghost, the Paraclete, the sanctifier of the faith of those who believe in the Father, and in the Son, and in the Holy Ghost. That this rule of faith has come down to us from the beginning of the gospel, even before any of the older heretics, much more before Praxeas, a pretender of yesterday, will be apparent both from the lateness of date which marks all heresies, and also from the absolutely novel character of our new-fangled Praxeas.

Tertullian
Against Praxeas
Chapter I

Christ, as God, descended to Hades so that we won’t have to

Now although Christ is God, yet, being also man, “He died according to the Scriptures,” and “according to the same Scriptures was buried.” With the same law of His being He fully complied, by remaining in Hades in the form and condition of a dead man; nor did He ascend into the heights of heaven before descending into the lower parts of the earth, that He might there make the patriarchs and prophets partakers of Himself. (This being the case), you must suppose Hades to be a subterranean region, and keep at arm’s length those who are too proud to believe that the souls of the faithful deserve a place in the lower regions. These persons, who are “servants above their Lord, and disciples above their Master,” would no doubt spurn to receive the comfort of the resurrection, if they must expect it in Abraham’s bosom. But it was for this purpose, say they, that Christ descended into hell, that we might not ourselves have to descend thither.

Tertullian
A Treatise on the Soul
Chapter LV

Christ is the seal of all prophecy and vision — nothing new is to come

And (then) “righteousness eternal” was manifested, and “an Holy One of holy ones was anointed”—that is, Christ—and “sealed was vision and prophet,” and “sins” were remitted, which, through faith in the name of Christ, are washed away for all who believe on Him. But what does he mean by saying that “vision and prophecy are sealed?” That all prophets ever announced of Him that He was to come and had to suffer. Therefore, since the prophecy was fulfilled through His advent, for that reason he said that “vision and prophecy were sealed;” inasmuch as He is the signet of all prophets, fulfilling all things which in days bygone they had announced of Him. For after the advent of Christ and His passion there is no longer “vision or prophet” to announce Him as to come. In short, if this is not so, let the Jews exhibit, subsequently to Christ, any volumes of prophets, visible miracles wrought by any angels, (such as those) which in bygone days the patriarchs saw until the advent of Christ, who is now come; since which event “sealed is vision and prophecy,” that is, confirmed.  And justly does the evangelist write, “The law and the prophets (were) until John” the Baptist. For, on Christ’s being baptized, that is, on His sanctifying the waters in His own baptism, all the plenitude of bygone spiritual grace-gifts ceased in Christ, sealing as He did all vision and prophecies, which by His advent He fulfilled. Whence most firmly does he assert that His advent “seals visions and prophecy.”

Tertullian
Against the Jews
Chapter VIII

The 2nd century Church prayed toward the east and worshipped on Sunday

Others, with greater regard to good manners, it must be confessed, suppose that the sun is the god of the Christians, because it is a well-known fact that we pray towards the east, or because we make Sunday a day of festivity.

Tertullian
Ad Nationes, Book I
Chapter XIII

The Lutherans saw their movement as not having introduced any innovations but only correcting abuses

Inasmuch, then, as our churches dissent in no article of the faith from the Church Catholic, but only omit some abuses which are new, and which have been erroneously accepted by the corruption of the times, contrary to the intent of the Canons, we pray that Your Imperial Majesty would graciously hear both what has been changed, and what were the reasons why the people were not compelled to observe those abuses against their conscience.

Augsburg Confession
Article XXI.X

Luther appeals to the long held Catholic tradition of the sacraments as an interpretive guide to the real presence

a. Moreover, this article is no doctrine or fixture (auff satz) dreamt up by men apart from Scripture, but is clearly established and founded in the Gospel through luminous, pure, undoubted words of Christ, and has been unanimously believed and held in all the world from the outset of the Christian church to this hour, as is proved by the books and writings of the dear Fathers of both Greek and Latin language and also by daily custom and the work of experience to this hour. This testimony of the entire holy Christian church (assuming we had no more than it) should alone suffice to attach us to this article and to move us neither to hear nor to tolerate any factious spirit on this matter. For it is a perilous and dreadful thing to hear or believe anything against the unanimous testimony, belief, and doctrine of the entire holy Christian church.

b. It would be a very dangerous to conclude that for so many hundreds of years the Church across all of Christendom did not have the right understanding of the sacrament.

Martin Luther
a. Letter to Duke Albrecht of Prussia, 1532
b. Opinion of 17 December 1534

The unraveling onion of the Reformation criticism of tradition

Like many of the Protestant critics who followed him, Semler could claim to be following in the footsteps of Luther and the Reformation, and to be doing so with greater consistency than the political situation of the 16th century had permitted the first Protestant reformers themselves to do. The same kind of historical–critical scrutiny to which Luther and his fellow reformers had subjected to cherished traditions and doctrines of the medieval church, such as the claims of the Papacy or even the sacramental system, could and should be rolled back to the very first centuries of the history of the church. Even the first century, revered as “apostolic,” must not be beyond the reach of historical criticism.

Jaroslav Pelikan
Whose Bible Is It?
The Canon and the Critics

The irony of pitting the Bible against the Church

Another aspect of the divine irony that we have seen repeatedly in the history of the use of the Bible within both Judaism and Christianity is that the Bible being used as a weapon against church and tradition had itself come from the arsenal of the church and had been preserved and protected by the tradition.

Jaroslav Pelikan
Whose Bible Is It?
The Bible Only

The Bible is not self authenticating

The very conflict over the biblical canon between the Protestant Reformers and the Council of Trent made it clear that even in a doctrine of sola Scriptura the authority of the Bible did not authenticate itself automatically (which would have required some kind of doctrine of repeated inspiration in each generation of the history of the church) but depended on recognition by tradition and by the church for acceptance.

Jaroslav Pelikan
Whose Bible Is It?
The Bible Only