The adversary is a master of propaganda. He revels in misinformation. He lives to deceive. If he can’t stop you he will try to send you in the wrong direction. He does everything in his power to conceal the truth.
And it should be evident that what is referred to in an overall general sense by an unsuspecting world as “Christianity” is actually a vast collection of unrelated, incongruent, disparate, and often contradictory elements, from merely human but also otherworldly sources, with no connection whatsoever to the original. Unreal Christianity is thus rife with untruths, half-truths, fruitless rituals, syncretic misapplications, and even what Paul referred to as teachings of demons.
The million or so separate Christian camps each have their own primary ideology and religious slant, and each, for the most part, declines close fellowship with the others for fear that its individual identity and brand will be diluted and weakened, and thus compromised toward funding and support. Many of these factions, some quite large, got started because some DA believed the whispered fabrications of the enemy or the weird ramblings of his own wayward mind and ran with them, taking many clueless hangers-on along for the ride.
Once such groups effectively progress from single dominator and analogous cultic origins to gain the desired reputable respectability and requisite numbers, a strange but perfectly understandable phenomenon occurs: The recognition, reception, and incorporation of greater truth, light, and correction is absolutely refused so as not to interfere with established success and acceptance. This only facilitates even more splintering off, the creation of new sects, and greater division. Thus, the multitudinous Christian factions of the last two millennia have more in common with the devil’s obfuscations and religious confusion than the Lord’s original teachings.
Therefore, if one wants to figure out what is what and which is which, one must be willing to do comprehensive, long-term, in-depth study of the Word of God and particularly the pure teachings of the Lord Jesus. One must investigate actual Christian history (not the fake constructs) in as much detail as possible. One must also do much wide-ranging research (much), with no vested interest or personal religious apologia, and wade through the ubiquitous, muddy, debris-laden waters of deception and misinformation to sort it all out.
In that process, as a byproduct of the search for truth, one will discover the frauds and the deceived. Their deceptive cloaking devices will fall away. They will no longer be concealed and they become completely exposed. This is exactly what happened with the Lord regarding the fake religionists of His time. He could see right through them. He could also apparently see demons, which, when you think about it, is really cool, since the devious imps were used to being invisible and getting away with all their lying shenanigans but could no longer hide—Anywhere. Whenever they attempted their magic disappearing act around the Lord it no longer worked.
Here’s just one example:
In the synagogue there was a man possessed by the spirit of an unclean demon, and he cried out with a loud voice, “Let us alone! What business do we have with each other, Jesus of Nazareth? Have You come to destroy us? I know who You are—the Holy One of God!” But Jesus rebuked him, saying, “Be quiet and come out of him!” And when the demon had thrown him down in the midst of the people, he came out of him without doing him any harm. And amazement came upon them all, and they began talking with one another saying, “What is this message? For with authority and power He commands the unclean spirits and they come out.” [Luke 4:33-36]
Think about this the next time you go to church.
It was therefore impossible to deceive Him. This is the way it must be for His real disciples. This is why the vast majority of those who claim to be NT Christians are not seeing Christians—they still have their blinders on. They can’t see the enemy. They remain deceived.
As a starting point in one’s search for truth and dividing truth from error, consider what the Lord told the frauds and deceived people of His time:
“Therefore I say to you, the kingdom of God will be taken away from you and given to a people, producing the fruit of it.” [Matthew 21:43] 
© 2017 by RJ Dawson. All Rights Reserved.
 Unless otherwise noted all Scriptures are taken from the New American Standard Bible, © 1960, 1963, 1968, 1971, 1972, 1973, 1975, 1977, 1995 by The Lockman Foundation. Used by permission.