In our constant struggle to believe we are likely to overlook the simple fact that a bit of healthy disbelief is sometimes as needful as faith to the welfare of our souls.
I would go further and say that we would do well to cultivate a reverent skepticism. It will keep us out of a thousand bogs and quagmires where others who lack it sometimes find themselves. It is no sin to doubt some things, but it may be fatal to believe everything...
Faith never means gullibility. The man who believes everything is as far from God as the man who refuses to believe anything.
Faith engages the Person and promises of God and rests upon them with perfect assurance. Whatever has behind it the character and word of the Living God is accepted by faith as the last and final truth from which there must never be any appeal... Thus faith honors God by counting Him righteous and accepts His testimony against the very evidence of its own senses. That is faith, and of such we can never have too much.
Credulity [gullibility], on the other hand, never honors God, for it shows as great a readiness to believe anybody as believe God Himself. The credulous person will accept anything as long as it is unusual, and the more unusual it is the more ardently he will believe. Any testimony will be swallowed with a straight face if it only has about it some element of the eerie, the preternatural, the unearthly. The gullible mentality is like the ostrich, that will gulp down anything that looks interesting: an orange, a tennis ball, a pocketknife open or closed, a paper weight or a ripe apple. That he survives at all is a testimony not to his intelligence but to his tough constitution.
I have met Christians with no more discrimination that the ostrich. Because they must believe certain things, they feel that they must believe everything. Because they are called upon to accept the invisible they go right on to accept the incredible. God can and does work miracle; ergo, everything that passes for a miracle must be of God. God has spoken to men, therefore every man who claims to have had a revelation form God must be accepted as a prophet. Whatever is unearthly must be heavenly; whatever cannot be explained must be accepted as divine; the prophets were rejected, therefore everyone who is rejected is a prophet; the saints were misunderstood, so everyone who is misunderstood is a saint. This is the dangerous logic of the gullible Christian. And it can be as injurious as unbelief itself.
The healthy soul, like the healthy blood system, has it's proper proportion of white and red blood cells. The red corpuscles are like faith: they carry the life giving oxygen to every part of the body. The white cells are like discernment: they pounce upon dead and toxic matter and carry it out to the drain. Thus the two kinds of cells working together keep the tissues in good condition. In the healthy heart there must be provision for keeping dead and poisonous matter out of the life stream. This the credulous person never suspects. He is all for faith. He accents the affirmative and cultivates religious optimism to a point where he can no longer tell when he is being imposed upon.
Along with our faith in God must go a healthy disbelief of everything occult and esoteric. Numerology, astrology, spiritism, and everything weird and strange that passes for religion must be rejected. All this is toxic matter and has no place in the life of a true Christian. He will reject the whole business without compunction or fear. He has Christ, and He is the way, the truth and the life. What more does the Christian need?