There is a strong cultural current that has crept into modern Christianity that promotes deep skepticism about truth, urging a pluralistic, even syncretistic, approach to spiritual truth in particular. And so, increasingly, the Great Evil in western Christianity is saying confidently, "I know the truth." Of course, the Christian who points at another believer and says "You're wrong to be so confident about spiritual truth," is asserting a truth claim, too, and, in my experience, often doing so with just as much confidence, just as much certainty, as the one they've criticized. Funny how that works out, eh?
Truth, though, is very often exclusivistic, requiring that if X is so, then Y cannot be. For example, if the hard rubber ball is entirely green, then the ball cannot also be, at the same time, a soft, silicone square colored red; if there are only two chocolates left in the box of Christmas chocolates, there can't be ten left in the box, at the same time; if Bob is a 6'2" biological male (a man) with blue eyes, he can't also be a 5' female (a woman) with brown eyes. And so on.
Especially where getting the truth wrong carries serious, negative consequences, folks are, generally, pretty careful to recognize the exclusivistic nature of truth. They won't bank at a place where arithmetic is a subjective thing, where 1+1=2 is an uncertain "truth" that is held lightly. No one wants a house-builder who has his own "truth" about measurement, and geometry, and load-bearing architecture. People object strongly to the idea of pharmacist who takes a casual, feelings-based approach to drug preparation and dosaging.
But when it comes to God's truth, to eternal, spiritual truth, an increasing number of "Christians" bristle at the person who says, "This is what God says." Under the influence of post-modern, relativistic, individual-centered secular thinking, these bristling believers hold doubt as a virtue, as something noble, even. And so, when they come to God's word, they do so often with a pretty radical certainty that no hard-and-fast truth can be extracted from it. Ironic that, eh? The one thing they are sure of is that one can't be sure of anything in the Bible. This is, though, an obviously self-defeating idea.
I don't see, however, in God's word any injunction to radical skepticism about His truth. It is implicit in so much of Scripture that both God and His truth can be known confidently, that as far as the revelation of both has been given to us, we can be entirely sure of it. How strange it is, then, when Christians want God's word, His truth, to remain amorphous, flexible, and open to syncretistic additions. This seems to me to be just a capitulation to the worldly idea of the "virtue" of radical skepticism, to the "nobility" of doubt. This thinking, though, is actually anti-Christian, against the plain declaration of God in His word:
Psalm 78:5-7
5 For He established a testimony in Jacob And appointed a law in Israel, Which He commanded our fathers That they should teach them to their children,
6 That the generation to come might know, even the children yet to be born, That they may arise and tell them to their children,
7 That they should put their confidence in God And not forget the works of God, But keep His commandments,
Deuteronomy 4:33-36
33 "Has any people heard the voice of God speaking from the midst of the fire, as you have heard it, and survived?
34 "Or has a god tried to go to take for himself a nation from within another nation by trials, by signs and wonders and by war and by a mighty hand and by an outstretched arm and by great terrors, as the LORD your God did for you in Egypt before your eyes?
35 "To you it was shown that you might know that the LORD, He is God; there is no other besides Him.
36 "Out of the heavens He let you hear His voice to discipline you; and on earth He let you see His great fire, and you heard His words from the midst of the fire.
Psalm 19:7
7 The law of the LORD is perfect, restoring the soul; The testimony of the LORD is sure, making wise the simple.
1 John 5:13
13 These things I have written to you who believe in the name of the Son of God, so that you may know that you have eternal life.
1 Timothy 6:3-5
3 If anyone advocates a different doctrine and does not agree with sound words, those of our Lord Jesus Christ, and with the doctrine conforming to godliness,
4 he is conceited and understands nothing; but he has a morbid interest in controversial questions and disputes about words, out of which arise envy, strife, abusive language, evil suspicions,
5 and constant friction between men of depraved mind and deprived of the truth...
2 Timothy 3:16-17
16 All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness,
17 that the man of God may be complete, equipped for every good work.
When the Israelites came to the borders of Canaan after a long trek through the wilderness from Egypt, they sent in spies to check out the Promised Land God had said was theirs for the taking. After the reports of the spies were given, the Israelites began to fear, doubting God's declaration to them that Canaan was theirs, that they had only to go in and possess it. The reports of great cities and peoples, of giants in the land, overcame all of the things they had just experienced in their journey out of Egypt to the Promised Land. Though God had taken great pains to show His Chosen People that He was with them, caring for, and protecting, them, they cowered at the prospect of claiming what God had given to them. They doubted God, and drew back in fear from His blessing, and this ANGERED God so much that He consigned the generation of doubters to life (and eventual death) in the wilderness outside of Canaan. (Read Numbers 13-14).
God has done much to give His born-again children clarity about what is true and good reason to be confident that it is true. And having done so, He expects them NOT to act like the Israelites at the border of Canaan, doubting Him and His truth, which is, essentially, to call Him a liar.
Not only has God given a sure revelation of Himself and His truth to us in Creation, the Incarnation and the Bible, but in the Person of the Holy Spirit, too, who "leads us into all truth," and in whom we possess "the mind of Christ," who strengthens us, teaches us, convicts us and comforts us daily, making us more and more like Jesus all the time (John 14:26; John 16:13; 1 Corinthians 2:10-16; John 16:8; Ephesians 3:16; Philippians 2:13; 2 Corinthians 3:18, Galatians 5:22-23, etc.) As a result, the genuine child of God has even less reason to doubt. S/he has both external, objective and authoritative witness to God and His truth and a direct, personal, internal witness to the same. For these reasons, the Christian who champions persistent doubt about spiritual truth, making it a virtue, even, to maintain a skeptical antagonism to any believer who says they know God and His truth is, in my view, widely off the mark about both God and His truth and what it is to know and walk with Him.