Allow me to take a stab at this question. How about, we don't HAVE to be either in order to understand the truth of the Word of God? The Gospel is so simple that even a child can grasp its message. God didn't go to the trouble of inspiring all those leaders and prophets and teachers to record the truths he wanted us to know, preserving his exact words for all this time, just to put it in a format that required learn-ed theologians or code-breakers to decipher. No, we don't NEED to be infallible or inerrant in order to have the inerrant and infallible truth of God's word touch our hearts and minds in Christ Jesus. He gave us his Holy Spirit so that those truths DO speak to our hearts and we are changed by their impact. They are our ONLY offensive weapon in this spiritual warfare - the Sword of the Spirit which is the Word of God.
No, we don't NEED to be infallible or inerrant in order to have the inerrant and infallible truth of God's word touch our hearts and minds in Christ Jesus.
Quite so. I explicitly deny being either an infallible interpreter of Scripture or an inerrant arbiter of doctrine. Yet even I can read the Scriptures, and through the Holy Spirit the truths therein can and does change my life.
That, however, is not the point.
From the First Century AD right up to the present day, folks can, have, and continue to read the Scriptures and arrive at contradictory and mutually exclusive beliefs regarding salvation, the nature of God, the nature of the Church, and many other topics. They cannot all be right. You tell me that none of them are infallible interpreters of Scripture or inerrant arbiters of doctrine. I tell you that God is not the author of chaos.
Either Jesus Christ is truly God, of the same substance as the Father ... or He is not.
Either Jesus Christ is truly Man, Son of Mary (and therefor "Son" of Adam) ... or He is not.
I have seen folks on this very forum arguing the "or not" position on both those questions. Their arguments were based on Scripture ... or at least their own interpretation therof.
I say they are wrong ... based on the authority of the Church, established by Christ and granted protection from doctrinal error by the Holy Spirit. Indeed, the Catholic Church, guided and protected by the Holy Spirit, resolved those questions almost two millenia ago. And on what basis? The Scriptures, of course. What else?
In the absence of an infallible interpreter of Scripture, we have no more reason to choose the teaching of the Church over the teaching of Arius.
That is why we need an authoritative teaching Church, established and protected by God ... and why God gave us one.
The claim that we (individual Christians) don't NEED to be gifted with infallibility is true. It's true because God gave us a Church, gifted with infallibility, protected by Him from error, to resolve dissputes.
Matt 16:18-20.
I would observe, then, that if (as you say) none of us on this forum are able infallibly to interpret Scripture or inerrantly define docrine ... then we all should be a lot more humble ... and a lot less eager to trumpet our own beliefs as the only "Biblical answer" while deriding those with whom we disagree as being "unscriptural" or having a "carnal mind". Protestants in particular, who (as you do) deny that anyone is able to interpret Scripture infallibly, should in fact be the most humble about their disagreements.