Origen (185-254) was a very early catechetical teacher. In his work De Principiis, he demonstrates that the truths of Catholicism have deep and early roots, whereas Protestantism does not. He upholds Church tradition and authority as the fundamental rule of faith for the teaching of correct doctrine and confirms the necessity of obedience for salvation.
All emphases are mine.
Before Origen proceeds to state the content of the Christian faith, he notes that their are differences of belief among people who call themselves Christians and thus sees it necessary to lay out an overarching rule for how to distinguish true from false doctrines:
Since many, however, of those who profess to believe in Christ differ from each other, not only in small and trifling matters, but also on subjects of the highest importance, as, e.g., regarding God, or the Lord Jesus Christ, or the Holy Spirit; and not only regarding these, but also regarding others which are created existences, viz., the powers and the holy virtues; it seems on that account necessary first of all to fix a definite limit and to lay down an unmistakable rule regarding each one of these, and then to pass to the investigation of other points…. [S]eeing there are many who think they hold the opinions of Christ, and yet some of these think differently from their predecessors, yet as the teaching of the Church, transmitted in orderly succession from the apostles, and remaining in the Churches to the present day, is still preserved, that alone is to be accepted as truth which differs in no respect from ecclesiastical and tradition.
Origen then, in Catholic creed-like fashion, says what the Christian faith holds to be true, careful to claim apostolic/Church authority for these doctrines:
Now it ought to be known that the holy apostles, in preaching the faith of Christ, delivered themselves with the utmost clearness on certain points which they believed to be necessary to every one…. The particular points clearly delivered in the teaching of the apostles are as follow…. Then, Thirdly, the apostles related that the Holy Spirit was associated in honour and dignity with the Father and the Son…. And that this Spirit inspired each one of the saints, whether prophets or apostles; and that there was not one Spirit in the men of the old dispensation, and another in those who were inspired at the advent of Christ, is most clearly taught throughout the Churches…. After these points, also, the apostolic teaching is that the soul, having a substance and life of its own, shall, after its departure from the world, be rewarded according to its deserts…. This also is clearly defined in the teaching of the Church, that every rational soul is possessed of free-will and volition…. [T]his beginning, itself, whether it be by birth or not, or whether bestowed upon the body from without or no, is not distinguished with sufficient clearness in the teaching of the Church…. Regarding the devil and his angels, and the opposing influences, the teaching of the Church has laid down that these beings exist indeed…. This also is a part of the Church’s teaching, that the world was made and took its beginning at a certain time, and is to be destroyed on account of its wickedness. But what existed before this world, or what will exist after it, has not become certainly known to the many, for there is no clear statement regarding it in the teaching of the Church…. Respecting which there is one opinion throughout the whole Church, that the whole law is indeed spiritual…. This also is a part of the teaching of the Church, that there are certain angels of God, and certain good influences, which are His servants in accomplishing the salvation of men…. Every one, therefore, must make use of elements and foundations of this sort…if he would desire to form a connected series and body of truths agreeably to the reason of all these things, that by clear and necessary statements he may ascertain the truth regarding each individual topic, and form, as we have said, one body of doctrine, by means of illustrations and arguments….
Notice at the end how Origen assumes the necessity of unity of true doctrine.
In talking of the end of the world, Origen also assumes the unity and authority of Church:
…if his mind be full of preconceptions and prejudices on other points, he may judge these to be heretical and opposed to the faith of the Church, yielding in so doing not so much to the convictions of reason as to the dogmatism of prejudice…. And in keeping with this is the declaration of the same apostle, when he exhorts us, who even in the present life are placed in the Church, in which is the form of that kingdom which is to come, to this same similitude of unity: “That you all speak the same thing, and that there be no divisions among you; but that you be perfectly joined together in the same mind and in the same judgment.”
He again upholds the authority of the Church when discussing corporeal and incorporeal beings:
We have now to ascertain what those matters are which it is proper to treat in the following pages according to our dogmatic belief, i.e., in agreement with the creed of the Church.
He again upholds the authority of the Church when discussing judgment and hell:
But since the discourse has reminded us of the subjects of a future judgment and of retribution, and of the punishments of sinners, according to the threatenings of holy Scripture and the contents of the Church’s teaching…. But now, also, for the sake of logical order in our treatise, there will be no absurdity in restating a few points from such works, especially since some take offense at the creed of the Church, as if our belief in the resurrection were foolish, and altogether devoid of sense; and these are principally heretics, who, I think, are to be answered in the following manner.
He again upholds the authority of the Church when discussing free will:
But as the preaching of the Church includes a belief in a future and just judgment of God, which belief incites and persuades men to a good and virtuous life, and to an avoidance of sin by all possible means; and as by this it is undoubtedly indicated that it is within our own power to devote ourselves either to a life that is worthy of praise, or to one that is worthy of censure…. Since in the preaching of the Church there is included the doctrine respecting a just judgment of God, which, when believed to be true, incites those who hear it to live virtuously, and to shun sin by all means, inasmuch as they manifestly acknowledge that things worthy of praise and blame are within our own power, come and let us discuss by themselves a few points regarding the freedom of the will
Origen also says that God demands fruit and labor from us, though He alone gives salvation:
So also in the race of our life we ourselves must expend labour, and bring diligence and zeal to bear; but it is from God that salvation is to be hoped for as the fruit of our labour. Otherwise, if God demand none of our labour, His commandments will appear to be superfluous. In vain, also, does Paul blame some for having fallen from the truth, and praise others for abiding in the faith; and to no purpose does he deliver certain precepts and institutions to the Churches: in vain, also, do we ourselves either desire or run after what is good. But it is certain that these things are not done in vain; and it is certain that neither do the apostles give instructions in vain, nor the Lord enact laws without a reason. It follows, therefore, that we declare it to be in vain, rather, for the heretics to speak evil of these good declarations.
He again upholds the authority of the Church and its complementarity with Scripture when discussing the human body:
For the faith of the Church does not admit the view of certain Grecian philosophers, that there is besides the body, composed of four elements, another fifth body, which is different in all its parts, and diverse from this our present body; since neither out of sacred Scripture can any produce the slightest suspicion of evidence for such an opinion, nor can any rational inference from things allow the reception of it, especially when the holy apostle manifestly declares, that it is not new bodies which are given to those who rise from the dead, but that they receive those identical ones which they had possessed when living, transformed from an inferior into a better condition.