For I do not seek to understand in order to believe, but I believe in order to understand. For I believe this: unless I believe, I will not understand.
To make it quite practical I have a very simple test. After I have explained the way of Christ to somebody I say "Now, are you ready to say that you are a Christian?" And they hesitate. And then I say, "What's the matter? Why are you hesitating?" And so often people say, "I don't feel like I'm good enough yet. I don't think I'm ready to say I'm a Christian now." And at once I know that I have been wasting my breath. They are still thinking in terms of themselves. They have to do it. It sounds very modest to say, "Well, I don't think I' good enough," but it's a very denial of the faith. The very essence of the Christian faith is to say that He is good enough and I am in Him. As long as you go on thinking about yourself like that and saying, "I'm not good enough; Oh, I'm not good enough," you are denying God – you are denying the gospel – you are denying the very essence of the faith and you will never be happy. You think you're better at times and then again you will find you are not as good at other times than you thought you were. You will be up and down forever. How can I put it plainly? It doesn't matter if you have almost entered into the depths of hell. It does not matter if you are guilty of murder as well as every other vile sin. It does not matter from the standpoint of being justified before God at all. You are no more hopeless than the most moral and respectable person in the world.
We may live in an age when everything has to be "radical" and "revolutionary." For Luther the most radical thing one could do was to learn the basics of the faith with the simple trust of a little child.
The ontological trinity will be our interpretative concept everywhere. God is our concrete universal; in Him thought and being are coterminous, in Him the problem of knowledge is solved. If we begin thus with the ontological trinity as our concrete universal, we frankly differ from every school of philosophy and from every school of science not merely in our conclusions, but in our starting-point and in our method as well.
But the best and only possible proof for the existence of such a God is that his existence is required for the uniformity of nature and for the coherence of all things in the world. We cannot prove the existence of beams underneath a floor if by proof we mean that they must be ascertainable in the way that we can see the chairs and tables of the room. But the very idea of a floor as the support of tables and chairs requires the idea of beams that are underneath. But there would be no floor if no beams were underneath. Thus there is absolutely certain prod for the existence of God and the truth of Christian theism. Even non-Christians presuppose its truth while they verbally reject it. They need to presuppose the truth of Christian theism in order to account for their own accomplishments.
It should not be forgotten in this connection that the minister's duty is increasingly that of an apologist for Christianity. The general level of education is much higher than it has ever been. Many young people hear of evolution in the high schools and in the college where their fathers never heard of it except as far as a distant something. If the minister would be able to help his young people, he must be a good apologete, and he cannot be a good apologete unless he is a good systematic theologian
How shortsighted and how uncultured, then, are the efforts of believers in Christ when they seek for snatches of worldly culture for themselves by placing themselves, as they think, on common ground with those who are not believers in Christ. How dishonoring to their Christ if they allow that any culture endures unless it be because of the power of his resurrection in the world. If you have been taken out of the miry clay, do you jump back into it because of some glistening objects that you see in it? Do you run back into the house now almost burned to the ground in order to save your silverware? It is only those who are believers in Christ that will inherit the earth and all the fulness thereof.
For what you have really done in your handling of the evidence for belief in God, is to set yourself up as God. You have made the reach of your intellect, the standard of what is possible or not possible. You have thereby virtually determined that you intend never to meet a fact that points to God. Facts, to be facts at all–facts, that is, with decent scientific and philosophic standing–must have your stamp instead of that of God upon them as their virtual creator.
If the God of Christianity exists, the evidence for His existence is abundant and plain so that it is both unscientific and sinful not to believe in Him.
If one does not make human knowledge wholly dependent upon the original self-knowledge and consequent revelation of God to man, then man will have to seek knowledge within himself as the final reference point. Then he will have to seek an exhaustive understanding of reality. He will have to hold that if he cannot attain to such an exhaustive understanding of reality he has no true knowledge of anything at all. Either man must then know everything or he knows nothing. This is the dilemma that confronts every form of non-Christian epistemology
I hold that belief in God is not merely as reasonable as other belief, or even a little or infinitely more probably true than other belief; I hold rather that unless you believe in God you can logically believe in nothing else
Suppose we think of a man made of water in an infinitely extended and bottomless ocean of water. Desiring to get out of water, he makes a ladder of water. He sets this ladder upon the water and against the water and then attempts to climb out of the water. So hopeless and senseless a picture must be drawn of the natural man's methodology based as it is upon the assumption that time or chance is ultimate. On his assumption his own rationality is a product of chance. On his assumption even the laws of logic which he employs are products of chance. The rationality and purpose that he may be searching for are still bound to be products of chance.The Defense of the Faith