Heresy looks like truth until you stand in the right place and see it for what it really is.
The apostle Paul makes this point as he warns the Colossians about false teaching. He switches back and forth so that the Colossians get a good look at the appearance of false teaching and then see the reality of it.
Watch how he does it...
"plausible arguments" (2:4)
"See to it that no one takes you captive by philosophy and empty deceit, according to human tradition, according to the elemental spirits of the world, and not according to Christ." (2:8)
"Therefore let no one pass judgment on you in questions of food and drink, or with regard to a festival or a new moon or a Sabbath." (2:16)
"These are a shadow of the things to come, but the substance belongs to Christ". (2:17)
"Let no one disqualify you, insisting on asceticism and worship of angels, going on in detail about visions, puffed up without reason by his sensuous mind." (2:18)
"He has lost connection with the Head." (2:19, NIV)
"If with Christ you died to the elemental spirits of the world, why, as if you were still alive in the world, do you submit to regulations--"Do not handle, Do not taste, Do not touch" (referring to things that all perish as they are used)--according to human precepts and teachings? These have indeed an appearance of wisdom in promoting self-made religion and asceticism and severity to the body." (2:20-23a)
"but they are of no value in stopping the indulgence of the flesh". (2:23b)
So where can you stand to see clearly the difference between the two?
There is only one place and it is right here:
"the knowledge of God's mystery, which is Christ, in whom are hidden all the treasures of wisdom and knowledge". (2:2b-3)
"Therefore, as you received Christ Jesus the Lord, so walk in him, rooted and built up in him and established in the faith, just as you were taught, abounding in thanksgiving." (2:6-7)
"in him the whole fullness of deity dwells bodily, and you have been filled in him, who is the head of all rule and authority". (2:9-10)