You seem to have a gap in your history.
There was a substantive period after Christ before there was a new testament - when tradition, that is the faith handed down by "word of mouth and letter" was the only christianity. So the early church was not a new testament church. Which is what catholics believe!.
Which is simply more absurdity!
1. While Caths seems to imagine that the church was an authority into itself with no prior established substantive authoritative standard for Truth, the reality is that established His Truth claims upon scriptural substantiation in word and in power. (Mt. 22:23-45; Lk. 24:27,44; Jn. 5:36,39; Acts 2:14-35; 4:33; 5:12; 15:6-21;17:2,11; 18:28; 28:23; Rm. 15:19; 2Cor. 12:12, etc.)
And which, as said, rather than being an authority into itself, the veracity of oral preaching by apostles was subject to testing by Scripture. (Acts 17:11)
2. The only wholly inspired record of what the NT church believed (including how they understood the gospels) is Scripture, specially Acts thru Revelation, not the words of some popes and councils, and which
Catholic distinctives are not manifest.
Thus, just as the NT church would have no validity unless the Lord and His church established Truth claims upon scriptural substantiation, so we must reject Catholic distinctives which lack this.
You also dodge the question of "what is scripture" and what documents are deemed heretical.
I did not dodge it, but all others so far have dodged my questions relevant to this, which is the premise that an ensured perpetual magisterial infallibility must be essential for knowing what writings as of God, and that being the historical stewards of Scripture means Rome is that authority. Which will be dealt with next, while even is that were so, then it would still mean that both the instruments and stewards of Scripture must be subject to it.
Which is why Jesus gave authority for the church - that is the succesors of apostles to answer doctrinal questions with the power to "bind and loose" to quote scripture. Which was the authority by which the canon you now call new testament was decided in council. And many documents and canons were also rejected by authority including the first! Marcions! Without the catholic church you would not have the new testament.
Which "we gave you the Scriptures-we are the infallible authority on it" is readily manifest as spurious, since the church actually began in dissent from those who sat in the seat of Moses over Israel, (Mt. 23:2) who were the historical instruments and stewards of Scripture, "because that unto them were committed the oracles of God," (Rm. 3:2) to whom pertaineth" the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises" (Rm. 9:4) of Divine guidance, presence and perpetuation as they believed, (Gn. 12:2,3; 17:4,7,8; Ex. 19:5; Lv. 10:11; Dt. 4:31; 17:8-13; Ps, 11:4,9; Is. 41:10, Ps. 89:33,34; Jer. 7:23) </p>
And instead they followed an itinerant Preacher whom the magisterium rejected, and whom the Messiah reproved by Scripture as being supreme, (Mk. 7:2-16) and established His Truth claims upon scriptural substantiation in word and in power, as did the early church as it began upon this basis. (Mt. 22:23-45; Lk. 24:27,44; Jn. 5:36,39; Acts 2:14-35; 4:33; 5:12; 15:6-21;17:2,11; 18:28; 28:23; Rm. 15:19; 2Cor. 12:12, etc.)
And which is certainly not opposed to magisterial authority, but the authority of the NT church was under men of supreme Scriptural integrity "not walking in craftiness, nor handling the word of God deceitfully; but by manifestation of the truth commending ourselves to every man's conscience in the sight of God. (2 Co. 4:2) "in all things approving ourselves as the ministers of God..." (2 Co. 6:4)
Which is what is lacking today. Catholicism presumes too much of an office, and too little of Scripture, the only substantive body of Truth that is affirmed to be wholly inspired of God, and in which she is substantially absent and contrary to.
Meanwhile evangelicalism presumes too much of Scripture as far as practical authority is concerned, and too little of the magisterial office established thereby. Time for greater repentance.
And the thousands of PROTESTANT doctrinal disputes on which every aspect of doctrine has mutually exclusive interpretations is proof that scripture is found wanting if you regard as "formally sufficient" - the premise of sola scriptura.
No, the sufficiency of SS is not restrict to what is formally provides, or least it would have to provide for reason itself. And as just explained, the "thousands of PROTESTANT doctrinal disputes...." polemic is spurious, due to the specious nature of the comparison, while beyond a faith in Rome, Catholics are an unholy amalgamation of brethren Rome considers members yet with variant interpretations of church teachings, while in contrast those who most strongly esteem Scripture as the wholly inspired and accurate word of God
testify to being the most unified in core beliefs. Why should be leave churches in which we can make distinction btwn false, liberal brethren and basically faithful, and join one which makes us brethren with Ted Kennedy types?
Take a simple aspect. Infant baptism. Scripture is not by itself clear, which proves the new testament is not, and never was intended as a complete manual. Or take priesthood.
The early church describes the role of bishops as the only ones (or their appointees) able to conduct valid eucharist. That clearly the teaching of apostle John through polycarp and ignatius. But you will struggle to find it in scripture.
Which is more absurdity! You do not define what the 1st century church believed by later uninspired words of popes and councils, and then judge Scripture by them, but you judge the uninspired words of popes and councils by wholly inspired Scripture, as noble Bereans did, and upon which the Lord substantiated His Messiahship by! (Luke 12:44)
Scripture is not sufficient alone except in the context of "material sufficiency"which is tacit admission it is not enough by itself.
Rather, it never meant formally sufficiency, for as
posted and ignored,
the Westminster Confession teaches, that the whole of Scripture provides (as public revelation) the necessary content for salvation and the life of faith, but which is not restricted to what it formally provides, and understanding it includes "the due use of ordinary means," while "there are some circumstances concerning the worship of God, and government of the Church, common to human actions and societies, which are to be ordered by the light of nature and Christian prudence, according to the general rules of the Word, which are always to be observed." (
The Westminster Confession of Faith (1647)