In these verses Paul developed the third error he already alluded to, namely, asceticism. The ascetic practices ("elementary principles," stoicheai, Colossians 2:8) he referred to seem to have been extensions of Mosaic Law. "If" ( Colossians 2:20) could read "Since." It is a first class condition in Greek that in this case is a condition true to reality. Christians "died" to merely human ordinances of Judaism and Gnosticism at conversion (cf. Romans 6:1-4; Romans 7:1-6; 2 Corinthians 5:14; Galatians 2:19). Nevertheless it is possible to put oneself under these and live like unbelievers in the world. The false teachers were in effect forcing the Colossians to live by the world system by placing ascetic requirements on them. The specific decrees cited as examples ( Colossians 2:21) have to do with food, but these are only representative of many such laws. These laws are inadequate for three reasons. The things prohibited perish through normal usage, the laws are of human origin, and they do not solve the real problem, namely, the desires of the flesh. [source][source][source]
"There is only one thing that will put the collar on the neck of the animal within us, and that is the power of the indwelling Christ." [1][source]
The emphases of these false teachers are still with us today. The first is "higher" knowledge (Gnosticism). The second is the observance of laws to win God"s love (legalism). The third is the belief that beings other than Christ must mediate between people and God (mysticism). The fourth is the practice of abstaining from things to earn merit with God (asceticism). [source][source][source]
"When we make Jesus Christ and the Christian revelation only part of a total religious system or philosophy, we cease to give Him the preeminence. When we strive for "spiritual perfection" or "spiritual fullness" by means of formulas, disciplines, or rituals, we go backward instead of forward. Christian believers must beware of mixing their Christian faith with such alluring things as yoga, transcendental meditation, Oriental mysticism, and the like. We must also beware of "deeper life" teachers who offer a system for victory and fullness that bypasses devotion to Jesus Christ. In all things, He must have the preeminence!" [2][source]
Reformed theology has historically taught that a true Christian will never renounce faith in Christ. The fact that Paul wrote this epistle to Christians who were in danger of doing precisely that should prove that this teaching is wrong. Nowhere in the epistle did he make a distinction between professing Christians, who were supposedly the objects of his warnings, and true Christians. Rather he appealed to the Colossians as genuine Christians to watch out for this real danger. Genuine Christians can be deceived by false teaching, even teaching concerning Christ. [source][source][source]