There is a book that summarizes the teaching of Herman Bavinck, called Our Reasonable Faith: A Survey of Christian Doctrine. I have read parts of the book but not all of it and I certainly do not claim to be an expert on the book itself. But the title is interesting. I don't know if this title was chosen by Bavinck or by later editors. "Reasonable" is used in variety of different ways. I don't think the the person intended to say that our faith is inexpensive (at least I hope not). Most likely, the idea is that our faith is rational and/or logical. Then there is the question of what is meant by "our faith?" Faith can be belief itself or that which is believed. Since the book is a survey of Christian doctrine "faith" must be referring to doctrines that are believed. So the book could be retitled The Rational Things That We Believe.
Referring to the Christian faith as rational things that we believe is entirely irrational. The sinful believer rejects the Christian faith because it is unreasonable and the sinful believer distorts and twists it to try to make it a little more reasonable but reasonable it is not. Some Christian apologists have written books in defense of the resurrection and some do a good job of showing the probability that Jesus actually rose from the dead. People probably would not have been willing to be tortured and killed for a resurrection that they knew did not really take place. Because of the resurrection we can be certain that what Jesus teaches us is true but that doesn't make the content of the teaching rational or reasonable.
The core teachings of the Christian faith have to be ignored before anyone can call them rational or reasonable. The agnostic is rational and reasonable, the polytheist can be rational and reasonable, the monotheist can be rational and reasonable, the Tritheist can be rational and reasonable, the Arian can be rational and reasonable, but the Trinitarian cannot. If Trinitarianism were reasonable the Athanasian Creed would say "The Father is God, the Son is God, and the Holy Spirit is God, so there are three gods." But it doesn't. It says that there are not three gods but one God. 1+1+1=3. God is three persons but only one being and there's nothing reasonable about that. I don't know of any other entity that is only one being but three persons. Even when well-intentioned and well-trained folks try to give examples to explain the Trinity they usually end up teaching a Trinitarian heresy--usually modalism. When the radio pastor comes on and starts trying to explain the Trinity by saying that he's both a father to a children and a son to his own father we end up with something very reasonable but absolutely not Trinitarian. But the Trintarian position is the only position that takes what all of the Scriptures say seriously.
The same is true when it comes to the doctrine of Christ. It is entirely unreasonable for someone to be completely God and completely man. The Nestorians and Arians and all the other guys have a much more reasonable understanding of who Christ is. Even the idea that God would take on a human nature is entirely irrational. It's insane. No lunatic would ever make it up.
But for some reason, even though God Himself is completely unreasonable, theological systems are constructed to make what God does reasonable. Why should we expect things to start getting more reasonable all of a sudden? The Calvinist and Arminian have both constructed systems to make the doctrines of salvation more reasonable which is the most irrational thing a person could possibly do. Just look at the bare bones of what we are working with:
1. God creates man.
2. Man sins.
3. God becomes man.
4. God dies to pay for man's sin.
There's nothing reasonable about any of that. This kind of makes sense:
1. God creates man.
2. Man sins.
3. God destroys man.
1. God creates man.
2. Man sins.
3. God says, "I'm God, why do I care?"
1. God creates a man incapable of sinning and they live happily ever after.
1. God doesn't create anything and just enjoys His perfect Trinitarian family.
All of these other options are reasonable but the truth is not. If the Scriptures teach that by nature we are dead in our sins shouldn't we just affirm that? If the Scriptures teach that God has elected a people for Himself from all eternity shouldn't we just affirm that (without speculating about an election to damnation)? If the Scriptures teach that Jesus came to take away the sins of the WORLD and to taste death for everyone can't we just affirm that? Since God dying for our sins does not make any sense at all, do we really think that we can figure out what is going on in God's head well enough to say that there were some He didn't die for? Since the Scriptures say that some people fall away from the faith can't we just admit that they do without trying to pretend they were never there to begin with?
I saw an advertisement on the local religious station for a financial guide based on the parables. I have not read the book but anyone who tries to draw financial principles from the parables should be checked into the nearest psychiatric ward. How is God portrayed in the parables? He's a crazy farmer who just starts throwing seeds everywhere. He throws them on the road, in the weed, to the birds. You go start a farm where you just start throwing seeds everywhere and let me know how it turns out.
God is also compared to a rich man who has a steward that is wasting away his money. The reasonable thing to do would be to escort the steward out of the building and perhaps try to sue him. Instead the rich man tells the steward to give Him a final accounting. The steward goes out and decreases everyone's debt by half. Now there is a rather lengthy list of reasonable things you could do to a steward like that. You could punch him in the face, stab him, etc. All of these would be reasonable things. Instead the rich man (God) expresses His admiration for what the steward did. He praises the steward.
What the steward knew is that his Master was not reasonable man. His Master was merciful. His Master was not stingy with His grace. His Master wanted him to trust in His mercy. If there were a guy who kept the books straight all the time (or at least thought he did) such a person would have no need for the grace of the Master.
All of this should humble us. We should be content to let Scripture speak to us and tell us what God wants us to know. Attempts at logical deduction as to what God can or cannot do are futile since He operates outside of the bounds of what is reasonable. The Scriptures are constantly warning against adding to God's Word.
1 Peter 4:11 If someone speaks, let him speak as announcing oracles of God; if someone provides service, let him provide it as deriving from strength that God provides, so that in all things God may be glorified through Jesus Christ; to whom belong the glory and the power forever and ever, Amen.
Do not introduce your sophisticated logical deductions--Bring God's Word!!! If you're not certain that you are speaking God's Word then shut up!
Deuteronomy 4:2 You shall not add to the word that I command you, nor take from it, that you may keep the commandments of Yahweh your God that I command you.
2 Corinthians 10:4-5 For the weapons of our warfare are not carnal but mighty in God for pulling down strongholds, 5 casting down arguments and every high thing that exalts itself against the knowledge of God, bringing every thought into captivity to the obedience of Christ,
The part in verse 5 translated as casting down arguments could literally be translated as "tearing down/demolishing reasoning." To hell with your clever reasoning! Your mind is an idol factory. How could you possibly trust it? Your mind is always tainted with sin and trying to make a god in its own image.
You must not only speak the truth about what is revealed but must remain silent about what is not.
Deuteronomy 12:32 Everything that I command you, you shall be careful to do. You shall not add to it or take from it.
1 Timothy 6:3-6 If anyone teaches a different doctrine and does not agree with the sound words of our Lord Jesus Christ and the doctrine which accords with godliness, 4 he is conceited, understanding nothing, but having a sick craving for controversies and word-battles, from which arise envy, strife, abusive speech, evil suspicions, 5 constant irritations between people of a corrupt mind and deprived of the truth, who think that religion is a means of gain. Withdraw from such people. 6 But religion with contentment is great gain.
If you teaching the same doctrine as Christ you should be able to use the same words as Christ and not explain them away. You should never be trying to tell people what Christ really meant because Christ knows how to say what He wants to say even if it is completely unreasonable. Where reasonableness is king, its even eviler step-sister pragmatism will no doubt rear her ugly head.
So rejoice in your unreasonable God! Only a completely unreasonable God would ever die for you! Only a completely unreasonable God could ever truly be God.