These are but four of countless such passages from the Word of God. And more important than any proof text is the fact that the whole import of the Scripture is toward this belief. We apprehend the physical world by exercising the faculties given us for the purpose, and we possess spiritual faculties by means of which we can know God and the spiritual world if we will obey the Spirit's urge and begin to use them. That a saving work must first be done in the heart is taken for granted here. The answer is our chronic unbelief.
Faith enables our spiritual sense to function.
Where faith is defective the result will be inward insensibility and numbness toward spiritual things. This is the condition of vast numbers of Christians today. No proof is necessary to support that statement. We have but to converse with the first Christian we meet or enter the first church we find open to acquire all the proof we need. A spiritual kingdom lies all about us, enclosing us, embracing us, altogether within reach of our inner selves, waiting for us to recognize it.