When the heretic Arius tried to defend his teaching at the Council of Nicea in 325 AD, that the λόγος (Logos - the Word), that is the Son of God, was a mere creature, the major reason why the Church rejected his doctrine was soteriology (the doctrine of salvation). That is, the revelation in holy Scripture concerning salvation in and through Christ was taken as the most convincing proof of all that the λόγος is God, one with the Father, "begotten not made." To the bishops there assembled, this confirmed the clear and plain meaning of Scripture beyond all doubt.
In the sixteenth century, something that Reformers had as a common task, no matter where they were, was the hard work of strengthening faith in the Christological doctrines that had been so thoroughly defended in the first four Ecumenical Councils (and consequently defended further in the last three). The need existed not because the Church in the west had forgotten any essential truth about God the Son, the Word made flesh, our Lord and Savior Jesus Christ. Indeed, every part of that doctrine was taught faithfully and fully.
But, just as a very strong drink can become weak through dilution, without taking away any of its properties, so the Christology in the Church at that time had become diluted through doctrinal confusion about soteriology. If the various Reformers, including our own English Reformers, are to have their message summarized by solas (which solas were not new at all in their time, but old established catholic teaching), it is not without cause that one of these is Sola Christi - Christ alone. No one else saves us from sin and death.
Of course, no one disagrees with this sola. Every theologian everywhere in the Church affirms the truth that only through Christ, only in Christ and only by Christ, can anyone be saved. Nonetheless, it seemed necessary to defend that truth even when it was not directly attacked or denied. Again, this is because the whole truth of Christology has been affirmed but, in subtle ways, at the same time diluted.
One major problem of taking a razor blade to Anglican sources, including the Thirty-Nine Articles, is that it is much easier to slice away those old writings than to learn the historical context that reveals their actual meaning. It is easier to react to Article XXV, for example, than to learn how even proper administration of the sacraments was restored by the English Reformers, including Cranmer's own radical and revolutionary idea of Frequent Communion for everybody in the Church (hence the name Holy Communion for the service; saying to all the faithful in Christ, come forward and receive).
In fact, the old formularies kept and preserved a true balance in which the place of the Church, and the sacraments "generally necessary to salvation," as well as the life of faith lived in the Church, were clearly taught and defended. Nonetheless, some Anglicans who intended to maintain obedience and loyalty to the formularies, appear to have lost sight of the sacramental ministry of the Church. That they lost sight of it in spite of, rather than because of, the writings of early Anglicans (including Cranmer, Jewel, Hooker, Andrewes), is all too clear to well read students of English theology.
But, on the opposite side, too many modern Anglicans accept uncritically the position of proselytizers from Rome, and teach the medieval innovations of a punitive Purgatory and the Treasury of saintly merits as if these things have Universal consensus, despite the fact that the Eastern Orthodox to this day reject them in the most clear language; or as if they were based on some sort of revelation equal to Scripture (needing Newman's theory of Doctrinal Development to make up for the lack of real authority), and as if that teaching can be consistent with the Gospel. Anglicans really have no business teaching any such system as the whole punitive Purgatory doctrine. It is "repugnant to the word of God," not because the Articles say so; but because of why they say so (that is one of those many things concerning which the Orthodox Church and Protestantism agree).
Let us consider the religious instruction that leads people to put their faith in various things rather than to repent and believe the Gospel. Do people really put their trust in the merits of saints? Someone may respond very well with the answer that their trust is really in Christ, and that saintly merits are merely a fruit of His grace, and really, thereby, trust in Christ. That is a very fine bit of reasoning indeed, and prevents the whole idea from being utter heresy and another gospel (Gal. 1:8,9). It is also a very thick addition of unnecessary water that can, in effect, dilute the Gospel command, that God "now commandeth all men every where to repent." (Acts 17:30) And, it can cause people to put their trust in something that prevents them from truly repenting, a form of passivity St. Bede warned against in many parts of his History of the English Church and People.
I qualify what I am writing about with the word "punitive." It is reasonable to interpret Scripture in such a way as to believe in a work of God by which we are purified, cleansed by the Refiner's fire; such is a work of His grace. But, that cannot be about satisfying justice. For punishment cannot be a necessary means to treat imperfections in those of whom it is written, "but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God." (I Cor. 6:11) If sins have been forgiven, what need is there of punishment, even if we tease the idea with the word "temporal" to soften it?
The whole doctrine of a punitive Purgatory, elaborately detailed as it was (and still is) by the Church of Rome, was a lucrative money maker both for the Church in Rome, and for relic salesmen. But, it had no other profit, certainly none for those who needed to know the way of salvation as God revealed it, and as the Universal Church had taught it for more than a thousand years (the real east-west consensus, that of the First Millennium).
But, the real problem, above all others, is that with salvation by Christ plus - whether it is saintly merits or anything added by anyone or anything else- the Church of Rome has fallen into the trap of a weak Christology. It is weak not through denial of the dogmas defended in Antiquity by the Universal Church. These it has held. To this day, Roman Christology is weak through dilution. The problem is so bad that the whole theory of Mary as a Co-Redemptrist or Mediatrix is taken seriously.
As I have written before:
"But, if Jesus Christ is fully God, the Word made flesh, Himself infinite and eternal, holy and separate from every created nature in his native Divine nature as one with the Father, made man by taking human nature into his eternal, infinite and holy Divine Person, then nothing can be added to the sufficiency of his 'sacrifice, oblation and satisfaction for the sins of the whole world.' To suggest that we have any need of a treasury of saintly merits from redeemed sinners and objects of the same mercy we have received, as if God owed a credit to sinful mankind due to alleged merits by the objects of his mercy and grace, is a frank denial of the Faith of the Church concerning Who is was that died for us and rose again."
So, it is not enough that we teach all that is true, that is to take nothing away from what God has spoken. It is equally necessary that we add nothing. "Every word of God is pure: he is a shield unto them that put their trust in him. Add thou not unto his words, lest he reprove thee, and thou be found a liar." (Prov. 30:6)