Do you believe in the inspiration, infallibility of Scripture; that the Bible you hold in your hands represents God's spoken revelation and hence it is without error or contradiction?
Where did the Bible come from?
Whose thinking does it reflect? God's or Man's?
Does it live up to its own claims?
Has Scripture been protected through the centuries from human tampering?
If the Bible in it's original manuscripts were written over an estimated period between 1500 years (1400BC? to 100AD?), what has prevented the text from being changed or altered in any way by man's carelessness or ill motives?
Let's look at how the bible explains itself:
7 The law of the Lord is perfect,
reviving the soul;
the testimony of the Lord is sure,
making wise the simple;
8 the precepts of the Lord are right,
rejoicing the heart;
the commandment of the Lord is pure,
enlightening the eyes;
9 the fear of the Lord is clean,
the rules of the Lord are true,
and righteous altogether.
10 More to be desired are they than gold,
even much fine gold;
sweeter also than honey
and drippings of the honeycomb.
11 Moreover, by them is your servant warned;
in keeping them there is great reward.
12 Who can discern his errors?
Declare me innocent from hidden faults.
13 Keep back your servant also from presumptuous sins;
let them not have dominion over me!
Then I shall be blameless,
and innocent of great transgression.
14 Let the words of my mouth and the meditation of my heart
be acceptable in your sight,
O Lord, my rock and my redeemer.
16All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, 17that the man of God may be competent, equipped for every good work.
2 Timothy 3:16-17
16For we did not follow cleverly devised myths when we made known to you the power and coming of our Lord Jesus Christ, but we were eyewitnesses of his majesty. 17For when he received honor and glory from God the Father, and the voice was borne to him by the Majestic Glory, his is my beloved Son, with whom I am well pleased,?18we ourselves heard this very voice borne from heaven, for we were with him on the holy mountain. 19And we have something more sure, the prophetic word, to which you will do well to pay attention as to a lamp shining in a dark place, until the day dawns and the morning star rises in your hearts, 20knowing this first of all, that no prophecy of Scripture comes from someone own interpretation. 21For no prophecy was ever produced by the will of man, but men spoke from God as they were carried along by the Holy Spirit.
2 Peter 1:16-21
So what is the Bible? Does it represent a hallmark of mere human literary achievement? Or is it indeed the inspired word of God, that is without error or contradiction, having been inspired and preserved by God himself?
If you adhere to the former, then there is a logical fallacy within your theology. If man's relationship with God is indeed fully conditional on the part of free will, and hence man at any time could fall into sin and thus lose his salvation altogether, why should we trust the inspiration of the Bible when in fact it's authors could have at any time simply lost their standing before God? Would not such a possibility open the door for the probability of the Bible not being fully inspired and innerant?
If the Arminian view of free will is correct, how can we say that the inspiration of scripture was genuinely safeguarded from human error unless God himself intervened in the thought processes of free men?
On the otherhand, if the above were not the case and scripture was written by people who had attained sinless perfection without God needing to directly intervene in their thinking, 2 Peter 1:20-21 would have to be wrong, thus making the Bible contradictory and containing error.
In conclusion, the best scriptural proof against pelagian theology and it's offshoots is simply the revelation, inspiration, infallibility and innerancy of scripture in of itself as it is a perfect representation between the relationship between God and Man.
It is also interesting to note how Peter regarded scripture; he saw the manifest glory of the Son of God with his own eyes, yet even so, he held God's inspired word as being more trustworthy than his own subjective experience.
By saying that "no prophecy of Scripture comes from someone own interpretation", he immediately shoots down any idea of bias within the scriptures on the part of the author. I've been to a lot of Bible studies where instead of examining the texts via historical and grammatical contexts, the focus is "What does it say to you", as though when you examine the scriptures according to personal opinion there may be the possibility of a subjective insight, and when these insights are mutually shared in a group setting the whole group supposedly becomes edified. Simple fact of the matter is that the Bible isn't written that way in the first place!