Secondly, I have some concern with the words, "as if there was some good from their teachings..." It cannot be said, Durelen, that heretical belief systems have no truth.
And that is the most dangerous; truth mixed with a lie. A great example of this is when the Devil tempted Jesus.
Matthew 4:5 Then the devil took him to the holy city, and set him on the pinnacle of the temple, 6and said to him, "If you are the Son of God, throw yourself down.
For it is written, He will give his angels charge of you, and In their hands they will bear you up, lest you strike your foot against a stone." 7 Jesus said to him, "Again it is written, You shall not tempt the Lord your God."
What was Satins tactic? He took truth and attempt to deceive Jesus with it. Yet we know that the Devil is a liar from the beginning but he is capable of using truth as well as deception. Of course in some of the teaching of false teachers there is truth, but it is in the spirit of deception. What may be said by them may have a completely different meaning than what scripture teaches even though it sounds familiar. The word of God is not a collection of sound bites in which we can pick and chose what is truth but it is a living, flowing, fountain of cohesive singularity. To add in a little poison corrupts the entire pool.
Yes, there are some full time ministries that deal with such things. I highly doubt you will see them sitting in services of such assemblies attempting to separate the truth from a lie to feed from the truth. Some believe this is perfectly fine in fact. And this in a day where approximately 85% of Christians have not the capability to coherently present the gospel in a witnessing situation. And with no capacity for the truth, how can they defend themselves from the thousands of doctrines of demons in this world? They wont.
1 Timothy 4:1 But the Spirit saith expressly, that in later times some shall fall away from the faith, giving heed to seducing spirits and doctrines of demons,
Why? Because there is some truth in what the seducing demons are saying. Enough truth mixed with a lie to twist the doctrines of our holy scriptures. Yes Ive met Christians who do such things. They read Dianetics, study with the Scientologists or with the Masons. Hey, truth is truth, right? It has some truth so it cant be all that bad. So we see 1 Timothy 4:1 coming true.
How did Jesus defend the attack of the Devil in Matthew 4:5? He did not learn its doctrine and try to reason from its twisting views; He used the pure Word of God. If you spent all your time running around trying to learn to defend the Gospel from every heretical teaching system, you would run out of gas long before you even bite off a chunk of the piles of rubbish. By using the Word of God you can defend the Gospel from EVERY false teaching known to man.
Hebrews 4:12For the word of God is living, and active, and sharper than any two-edged sword, and piercing even to the dividing of soul and spirit, of both joints and marrow, and quick to discern the thoughts and intents of the heart.
That is all you need to be prepared to defend the Gospel from any perverted doctrine. When I pick up an apologetic book on cults or false teachings I see a record of battles. I see the tactics in which they use that have been used for thousands of years. I feel the clash of steel on steel and the fallen on the field, stricken even unto death. Hosts of demons manning their barricades and courageous Saints marching into the breach armed with the Sword of the Spirit.
Ephesians 6:12 For our wrestling is not against flesh and blood, but against the principalities, against the powers, against the world-rulers of this darkness, against the spiritual hosts of wickedness in the heavenly places.
And to be well armed you must use the Sword of the Spirit which is the Word of God, as well as the whole armor of God. There is no substitute or upgrade; its the best.
Ephesians 6:13Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand. 14Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness; 15And your feet shod with the preparation of the gospel of peace; 16Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked. 17And take the helmet of salvation, and the sword of the Spirit, which is the word of God: 18Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints
We should be praying for revival, not trying to learn truths from doctrines of demons.