Why are Christians so gullible and so prone to deception? What could possibly be behind it?
First, because the foundation of the Christian life is belief. However, that we can believe the wrong things is made abundantly clear by the Bible. We must know what we believe and why and that we are believing the right things. We cannot just believe anything. Our objects of faith must be God and His Word, not mere men or wild claims. Dr. Bruce Bickel reminds us: “Too often what passes for unity is really compromise. It is better to be divided by truth than united in error.” 14
Second, the Christian is commanded to love. Love tends to be accepting and is willing to overlook. However, love that is not structured in truth is sentimentalism and is so wishy-washy it can be manipulated and led astray.
We cannot confuse love and emotionalism or love and feelings. Love is a commitment to truth and the highest good of others. Love does, as Scripture attests, “cover a multitude of sins.” 15 At times, that love means bringing a sinner back from the error of his ways. 16 Love will not tolerate false teachings or lies which in the end hurt and destroy others. Biblical love insists on truth and true doctrine.
Third, we have a tendency to want to believe Christian leaders and Hebrews:13:7Remember them which have the rule over you, who have spoken unto you the word of God: whose faith follow, considering the end of their conversation. indicates that generally we should. However the verse alerts us to be aware of their conduct as well. So it is not a blind following. Is the leadership we are following really modeling Christ and the Bible? Paul said we are to follow him “ as he followed Christ.” As commendable as it is to love and trust our leaders, we still have to be Bereans (Acts:17:11These were more noble than those in Thessalonica, in that they received the word with all readiness of mind, and searched the scriptures daily, whether those things were so.) and test all messages against Scripture. We do our leaders a great service by being mutually accountable. Leaders are vulnerable without the help and balance of others.
Fourth, we can be brainwashed by religious television and are being told that to question is “heresy hunting” or it is a “religious spirit” or “white cane religion” or a “Jezebel spirit” or worse. We are cowed by being threatened with the possibility of committing the blasphemy against the Holy Spirit even though we are just trying to be discerning. We should not be manipulated by a turning of the tables and a guilt trip laid on us for questioning heresy. We should not be in a church where there is no accountability or church discipline. In that setting, unrepentant sinners and autocrats are “above the law.”
Regrettably, very little stress is being put on the gift of discernment. All Christians are called to be discerning. We must check things out (1 John:4:1-6  Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world.
 Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God:
 And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.
 Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world.
 They are of the world: therefore speak they of the world, and the world heareth them.
 We are of God: he that knoweth God heareth us; he that is not of God heareth not us. Hereby know we the spirit of truth, and the spirit of error.
Fifth, it is hard for us to believe or imagine that slick magazines such as Charisma could be peddling deception and that such wonderful ministries (as being advertised) could not be on the up and up. It is hard for us to believe that “Christian” bookstores could be part of the problem. It is hard for us to believe that all the money being made is the reason for the collusion (and the advancement of the wild and weird). It is amazing that books teaching occult doctrine are now being marketed as “Christian classics.”
14. Bruce Bickel in the preface of Don Kistler, General Editor, Sola Scriptura . Morgan, Pa.: Soli Deo Gloria Publications, 1998, pp. xi-xii.
15. Proverbs:10:12Hatred stirreth up strifes: but love covereth all sins., 1 Peter:4:8And above all things have fervent charity among yourselves: for charity shall cover the multitude of sins..
16. James:5:20Let him know, that he which converteth the sinner from the error of his way shall save a soul from death, and shall hide a multitude of sins..
17. Sola Scriptura , op. cit., pg. xii.