[See the start of this thread and comments here.]
Let me take your points as you’ve presented them.
(Asking the intercessions of the “dead.”)
The Church has always interpreted Hebrews 12:1 (on the basis of the faithful of the Old Testament who have died and gone before us spoken of in chapter 11) as that the many witnesses are the “dead” who are alive in Christ God. Furthermore, Revelation 8:3-4 speaks of the prayers of the saints going up as incense before the Lord. In context, it is probably best to interpret these saints as the martyrs of 6:9-11 and 7:13-17. And while it is true that the content of their prayers are not manifest (except maybe for the justice of God to be realized as pace chapter 8, if the dead who are alive in Christ are witness to our struggles in the race set before us, it seems reasonable to conclude that they pray for us as well. After all, in this life they were charged by the Apostle Paul to offer “supplications, prayers, intercessions, and thanksgivings . . .on behalf of all men, on behalf of kings and all those who are in authority, that we may lead a tranquil and quiet life in all godliness and dignity. For this is good and acceptable before God our Savior, who desires all men to be saved and to come to the full knowledge of the truth” (1 Timothy 2:1-4). On what basis would they be free of this obligation simply because they are now with God in the heavenlies? These intercessions do not in anyway negate Christ’s mediation, for these prayers are offered precisely on the basis of such mediation, as Paul goes on to say, “For there is one God and one Mediator between God and men, the Man Christ Jesus, who gave Himself a ransom for all, the testimony in due time . . .” (1 Timothy 2:4-5). We no more short circuit Christ’s mediation to us by asking the prayers of our presently alive Christians brothers and sisters, than we do asking those who’ve gone before us, absent from the body but present with the Lord (2 Corinthians 5:8), to pray for us.
More to the point, asking the intercessions of those who’ve gone before us is a practice directly testifying to the victory of Christ over death, that is to say, a faith in the Resurrection. It would seem that, despite good intentions, to forbid the invocations of the saints who’ve gone before us precisely because they have died is to deny the present reality of Christ’s victory over the last enemy. It means death is stronger than Christ. But Paul has something to say about that: Romans 8:37-39.
(Sufficiency of Oral Transmission)
As you acknowledge, your argument depends upon your own assumptions. You then think to bolster your claims by asserting that I assume the efficacy of oral transmission, thus invalidating my own claims.
But I see that you continue to fail to deal with the actual historical evidence I present. You seem to assume that since the NT Scriptures were written down within the first two generations of the Church (from, presumably, A.D. 50s-90s), that all had ready access to those Scriptures. This is not the case. In point of fact, for the first several centuries in the Church, the bulk of Christ’s Body was illiterate, nor of sufficient means to own the entirety of the Old and New Testament Scriptures. At most, a particular local Church would have copies of one of the canonical Epistles written to them, as well as other canonical writings associated with them. Thus we can presume that the Church in Ephesus would have had the epistle to the Ephesians (if we assume the ascription to be genuine), perhaps the letters to Timothy who was their bishop, and the Gospel of the John, to whom Tradition ascribes to the Apostle, and whom himself was a leader at Ephesus. This in itself would have been a rich storehouse. And it does seem that the body of Paul’s Epistles did circulate widely and early. Nonetheless, your argument requires that all the OT and NT Scriptures be available to all the Churches within the first generation or two of the Church. If they weren’t then most of what they had to go on was the Tradition. And, in fact, this state of affairs held true for some time, especially for those Churches far outside the geographical communications with the major urban centers. The Scriptures the early Christians received was mostly that which they heard as the Liturgy and in the Liturgy.
So, in the end, the argument from history must be greater than your argument from silence and assumptions. Indeed, if oral transmission is insufficient to ground Apostolic Truth for two millennia, it would hardly be scandalous to say that it insufficient to ground such for two centuries. And yet, for two centuries, the Churches of God had slightly differing canons of what constituted God’s NT Scripture, and nearly all were without the entire Church’s full canon. Yet, mirabile dictu, without the Scriptural evidence necessary from your own argument to substantiate your claims, they were guided surely and rightly to the full canon and to the fullness of the Aposotlic Faith.
(Sufficiency of Scripture for faith and practice)
I agree with much of what you have to say, except for this claim: “I find it rather ironic that it is the Protestant church that has not tampered with the traditional canon as recognized by the ancient Jewish church.” It’s clear that you have not studied the history of OT canonization, nor of the recent history of the recovery of the Dead Sea Scrolls and their contents. These resources are readily available, so I will simply summarize here: The OT canon as most all Protestants use (less the so-called “Apocrypha” or “Deuterocanon”) was not promulgated till at or after the council of Jamnia c. A.D. 90-ish (if I recall correctly), itself a reaction to Christianity. The almost-exclusive use of the LXX by the Apostles (itself readily attested by the NT), gives tangential support to the fuller canon, but even more to the point, the early Church itself readily and often used these texts, and included them in their copies of the Scriptures. Not until Martin Luther and other Reformers threw them out, in reaction to the real and perceived excesses of the Roman Church, did any part of the Church reject them. Again, history and Church practice is on the side of the fuller OT canon.
But to the point of your argument, that Scripture itself is “ sufficient for the faith and practice of the Church” cannot be in any way justified from Scripture itself. I need not prove Scripture to be insufficient in itself, because a) it creates a false dichotomy between Scripture and Tradition which I don’t accept, and b) I’m not denying the sufficiency of Scripture but rather pointing out to you that your argument does not work on its own terms. I need prove nothing if your argument cannot stand on its own. And it clearly does not. So, on your own terms, you cannot claim what you do about Scripture.
Furthermore, your argument falls apart when you admit, “I have no problem with non-Apostles transmitting apostolic Tradition, even if such transmission is oral. Given the incomplete status of Scripture at the time, this would have been necessary. Conversely, given that Scripture is now both complete and sufficient, I would argue that if it’s not in Scripture, then whatever is being transmitted is not apostolic Tradition.” You are caught in an irresoluble dilemma, for if oral transmission is fine until the completion of the canon, then it must be fine afterwards. That you assume it is fine before but invalid after is a circular argument which is invalid. Furthermore, you either do not mean by “completion of Scripture” the writing of the last canonically received text (presumably John’s Gospel), because even if Scripture were then complete, it would make no practical difference to those who did not have the complete canon. So you must mean that the completion is when the final canon was authorized, but then you have oral Tradition, for the most part, for some three centuries after the start of the Church. But if oral Tradition is good for a few hundred years, it must be good for longer than that.
But once again, this is not a claim you can even substantiate from your premise of Scripture alone being the Tradition, because Scripture alone does not ever say that.
(Fallibilty and Infallibility)
The infalliblity of the Church founded upon the claims of Scripture itself, and thus should be authoritative for you. Cf. the following:
Matthew 18:15-20: Here Jesus speaks of the Church judging certain disciplinary matters. And whatever the Church decides, Jesus says, “Assuredly I say to you, whatever you bind on earth shall have been bound in heaven, and whatever you loose on earth shall have been loosed in heaven. Again, assuredly I say to you that if two of you agree on earth about anything that they may ask, it will be done for them by My Father in heaven. For where two or three are gathered together in My name, I am there in their midst.” The decision, then, is an infallible one; i. e., “bound/loosed in heaven and on earth.”
1 Timothy 3:15: Perhaps the most explicit reference in Scripture of the Church’s authority vis a vis the truth: “the house of God, which is the church of the living God, the pillar and bulwark of the truth.” Why is the Church called something Scripture never is? Because, primarily of John 14:6: Jesus calls himself, “the Truth.” The Church is the Body of Christ, and therefore by her participation in the Truth (Christ), is herself, as a whole, “the pillar and bulwark of the Church.” This is not to downplay or mitigate the authority of Scripture, for Scripture, too, participates in the divine Life, as it is “out-breathed” from God. Again, I need not resort to false dichotomy. I own both the infallibility of Scripture and of the Church. You, however, are forced by your own argument to deny the Church’s infallibility so as to make way for the sole infalliblity of the Scriptures. Yet Scripture itself witnesses to this infalliblity, this grounding of Truth in and on the Church as she eternally participates in Christ.
How does the fallibility of men become the infalliblity of the Church? In short, the mystery of divine Grace, but Christ himself indicates that it is by the participation in Christ that the Church, as a whole (remember it is the “whole church” in Matthew 18) that individually fallible members are gifted in the Church as the Church with infallibility. That is, they teach not their own opinions and private interpretations (2 Peter 1:20ff), but the mind of the Church, which has put on the mind of Christ (cf. Philippians 2:5; Ephesians 4:13-15).
(Limiting the Tradition to the Body of Scripture)
The point I was trying to make, however, is that the Tradition they received, they received prior to the completion of the inscripturation of Scripture. That these points later were inscripturated does not invalidate my case, so much as strengthen it. It was by oral transmission of the Tradition that they received these things. And when they received these written Scriptures, how were they to verify their authority and divine origin? By way of the Tradition; i. e., Tradition substantiated itself in Scripture. This process, by the way went on long after the “closing” of the inscripturation process, as the testing of various books for inclusion in the canon went on for a few centuries. So, if we must force ourselves into stating these things according to the setup of your argument, it is the Tradition that is the foundation of the Scripture, not the other way around. This, at least, is the historical record.
Furthermore, the Tradition cannot be coextensive to the Scripture since there are many more things necessary for faith and belief than are clearly enjoined in Scripture. There is little to no warrant, on the basis of Scripture alone, for assigning to Sunday the day of the primary gathering of Christians for worship (a note you ignored in my previous post). Or if there is, there is much more warrant for believing that the elements of bread and wine become the Body of Christ in the Eucharist and the grace of God toward salvation is given to the recipients of baptism in the baptismal act. Yet how many Protestants deny these very things? (I do not know if you are one of them.)
But more to the point, there is no warrant in Scripture itself, and on this your whole argument hangs, that Tradition is coextensive with itself. Book-chapter-and-verse me, my friend, on that one.
(Obsolescence of Tradition Based on Completed Canon)
You still fail to make valid arguments.
Premise 1: If Scripture is incomplete, then Tradition is necessary.
Premise 2: Scripture is complete.
Conclusion: Tradition is unnecessary.
But here you have denied the antecedent (i. e., Scripture is not incomplete), which is an invalid argument.
You also, frankly, create a false dilemma, that one must choose between a completed canon and an oral Tradition that speaks to both those things Scriptures do address, and those they don’t.
By the way, your claim that we know Paul’s apostleship was part of the Tradition via Scripture is true, but it is not true of those who knew Paul prior to inscripturation. They knew Paul’s apostleship was from God via holy Tradition, not Scripture.

