In addition to what has been said above, there is another point to be made about the integrity of a Christian's faith that is often neglected. Too often we readily recognize the need to love the LORD with all of our hearts, but this is incomplete, and consequently so will our faith be in such a condition. Jesus said we are to "Love the Lord your God with all your heart and with all your soul and with all your mind (Matthew 22:37)." How do you we love the LORD with all of our mind? The Greek word for mind used in this passage of Matthew is dianoia, and means exactly what you would expect: the mind as a faculty of understanding. So to love the LORD with all of our mind is to submit our rational faculties to the pursuit of the knowledge and understanding of God, His nature and person. Since human beings are a multi-faceted entity as designed by God in reflection of His image, we ought to strengthen our minds through the reasons we have for our faith, as the apostle Paul (Acts 17:2), disciples (1 Peter 3:15), and Jesus Himself (John 10:38, John 14:11) urged. By strengthening our faith through understanding of the truth, we reconcile the contending parts of ourselves that constantly weigh and reweigh evidence, feeling, intuition and conviction and allow our heart and mind to function in unison to affirm the truths of the Christian faith. This is abundantly beneficial to the Christian and providing them the strength and conviction they need to stand in all circumstances and contend for the faith against all opposition and adversity. I can attest to the power of an intellectually developed and considered life in our faith personally.
That said, consider this: Since God created us, the universe that surrounds us and everything extrinsic to Himself, everything in all existence derives it's being from God in its entirety. This includes the entity inside of our flesh we call the brain, which was created to be our fleshly container in which we process our thoughts, emotions and the world around us. This brain in which we contain all of our cognitive capacities and functions was provided by God all of its abilities and limitations, not only in its ability to apprehend a range of truths but in its ability to be employed to apprehend categories of truth (this point is very important so read carefully, and, if you understand, I can assure you from personal experience no such doubt will ever be able to penetrate your mind again). What I mean by ranges of truth is our brains capacity to be used to process information at certain speeds, the amount of information our brain can hold simultaneously, how efficient our thought processes are, how much access we have to our subconscious, etc.; Our quantitative abilities. What I mean by categories of truth is what we can apprehend to exist at all which we can extend the range of our capacities through to apprehend knowledge about such matters. To provide an example, the range of our cognitive capacities concerning moral truths would be applied to discriminating between events and actions to determine the moral quality of those events and actions; our cognitive capacities concerning categories of truth in this instance would be the ability to understand that their is a moral realm to apprehend at all.
Thus, if God wanted to deceive you, being the designer of your cognitive functions and capacities in their entirety, He would not even have to try. All God would have to do to deceive humankind is provide them cognitive capacities so limited that they would be absolutely unable to apprehend His deception if He were to flaunt His malevolent motives before their eyes all day long. So what you have to ask yourself is this: If God wanted to deceive me, why would He provide me the cognitive ability to discriminate between truth and falsehood with such accuracy that I would be able to discover His deception? The truth is, doubt exists for only two reasons: Ignorance and free agency. Either we are simply lacking in knowledge and unable to understand why God is abundantly worthy of our absolute trust, or we simply choose to deny Him and His testimony. This decision or ignorant response of doubt never results from rational investigation. So I would urge you, like the apostles, disciples, and Jesus Christ Himself to rationally consider all of the evidence we have for our faith and why God is worthy of that faith.
In summary, God is the author of the same cognitive functions that we must use to doubt Him or impose our perspectives onto His creative decree (how we think things ought to be), wholly by the use of the tools provided by His decree of our minds. When you consider this, it should occur to you that there is literally no more of an absurd use of our minds than to use them against the one who constituted them, to doubt what He has revealed of Himself or the perfection of His will. It's actually quite laughable, and I found impulses to doubt to be nothing more than amusements at the realization of this truth. This is not at all said to criticize you, but to help you. As Jesus said, "If you hold to my teaching, you are really my disciples. Then you will know the truth, and the truth will set you free (John 8:31-32)." And, " if the Son sets you free, you will be free indeed (John 8:36)." So hold to His teaching, because by the evidence of His life, the testimony of the Holy Spirit, and the overwhelming rational warrant we have for assent to this testimony, we can know with certainty that He is who He claims to be.
