Without faith reasoning becomes impossible. So do I believe this on the basis of reason or faith? Well, it all depends on how you want to state it. I believe it on the basis of faith, but faith which saves reasoning and, therefore, it’s the most reasonable thing to do. So that’s my reason for having faith. Is my intellect my ultimate authority then? No, faith and the word of the Lord is. And my reason for holding to that is, reason itself is destroyed if you don’t.
Do you have faith or do you have reason, Dr. Bahnsen, for being a Christian? I say, well, it’s a matter of faith. It’s a faith without which reasoning would be impossible. Now since reasoning would be impossible without this faith, then ultimately the best reason according to reason is to have faith. And those who do not have this faith destroy reason. But that doesn’t mean that I am following Christianity because it satisfies my reasoning as the ultimate authority.
Dr. Greg Bahnsen, Seminary Course in Apologetics, Lecture 5.