Perhaps you've come across this argumentative strategy that cautions that if evangelicals opt for any other articulation of biblical authority than traditional inerrancy than a slippery slope to "liberalism" and "unbelief" becomes unavoidable:
"But direct conflict with Scripture is not the only difficulty that limited inerrancy faces. It faces other difficulties due to the over-arching role of God’s words. One significant point made in the Bible is that other things besides the Bible are God’s words. God’s word includes (a) words of Jesus not recorded in the Bible (John 21:24–25), (b) the direct speech of God to Abraham, Moses, and others when he appeared to them (“personal address”), (c) God’s word of power by which he rules the universe (Heb. 1:3; cf. Ps. 33:6), and (d) the Son, the Second Person of the Trinity (John 1:1, Rev. 19:13). If the Bible, the word of God, contains muck, perhaps some of these other words contain muck too. How can we be sure that they don’t? Several positions are possible.
A. Muck (or the possibility of muck) is in fact introduced only when there is a human intermediary such as Moses or Paul. God’s words of personal address and God’s ruling word of power are always and infallibly free of muck.
B. Muck may occur even in God’s words of personal address to Abraham, Moses, etc.
C. Muck may occur even in God’s words in the intra-Trinitarian communication, and in God the Son.
All these positions have difficulties of a severe kind. The most serious is C. To be sure, we must remember that the muck consists only in complete nonessentials, in details of the minutest kind. But nevertheless, the conclusion is inescapable: God himself is mucked up. The Persons of the Trinity do not communicate exhaustively. Consequently, a separation is introduced in the Trinity, and one obtains incipient tritheism. If the Son alone has muck, one descends to a form of Arianism.
Let us see where position B leads. Can muck occur also in God’s words to other creatures besides men? Only men are fallen, it is true, but creation is under a curse. And one must remember the possibility that muck is introduced by man’s ignorance as well as by his sin. Other creatures are still more ignorant than man, so may we suppose that there is more muck? Perhaps, then, there is muck scattered through the word of power by which God upholds the universe. If the clear passages speaking of the purity of the Bible do not exclude muck, much less can we exclude muck from these other words, which are much less essential to salvation.
But see how disastrous this is. Nothing at all happens apart from God’s will (Eph. 1:11), or apart from God’s command (Lam. 3:37–38; cf. Ps. 147:15, Heb. 1:3). Hence everything gets contaminated with muck." (V. Poythress, "Problems For Limited Inerrancy,"JETS 18 : 93-102, http://www.frame-poythress.org/poythress_articles/1975Problems.htm)
Poythress takes two morals away from the discussion:
1) "[I]t is easy for the guns of criticism employed by limited inerrantists to be selectively aimed at the Bible, far more than at their modern environment, their own techniques, their own ethical standards, their own persons, or their own language. It is easy to imitate the bulk of critical scholarship that practices selective aim. But one wonders whether it is conducive to a healthy spiritual attitude."
2) "[M]uck can be conclusively found in the Bible only by those who have some source that is in some respect more free of muck than the Bible itself."
Regarding (1), there may very well be no objective set of criteria that I can articulate that works in every case to tell us when and when not to employ criticism. Such criteria may not be forthcoming. Yet I have found that using "the guns of criticism" to explode the inerrantist ultimatum to be highly conducive to a healthy spiritual attitude. I say with full assurance that gaining freedom from the inerrantists' reins can prove highly beneficial to a number of believers. Just because one finds some fault with the scriptures does not necessitate the full blown use of criticism on every part equally. If a friend makes a few mistakes, it is not always necessary now to question every single action and motive relentlessly. The non-inerrantists I write for are not interested in destroying the friendship; quite the contrary, we are trying to make it work!
Regarding (2), this idea of having an ultimate source of revelation is confused, I think. We all use our reason and experience to make judgments, even inerrantists do this. Everybody has to make genre judgments, everybody has to decide whether something in scripture is intended literally or figuratively, everybody has a decision to make with regard to whether some biblical stipulation applies today or not. We are all in the same boat. That's what my book tries to highlight: that oftentimes it's tradition that floats the boat not inerrancy. There is no gain in upholding an authoritative line of tradition under the pretenses of an inerrant Bible. Right now it seems to me that a non-inerrantist would have more critical freedom to admit this and less fear to see the Bible, warts and all, with a chance, perhaps, of better understanding what the Bible actually is as it has actually been given to us.
I think there is too much freedom in this position for inerrantists. Too much potential chaos, uncertainty, muck. But that seems to be the kind of life that Christians have been given. God is not waiting to strike every believer's muck with a bolt of lightning. We are free to talk about these things and investigate: figure out where to go from here. It's about time (isn't it?) that younger evangelicals be given some pointers on how they might begin living this kind of uncertain and chaotic life in Christ.