"Therefore no one is to act as your judge in regard to food or drink or in respect to a festival or a new moon or a Sabbath day — things which are a mere shadow of what is to come; but the substance belongs to Christ." (Colossians 2:16-17)There are some believers who feel it is their purpose in life to examine and judge other believers. Their goal is to test each believer against what they believe is the standard of Christian behavior (which is most often their own standard of behavior) and to pronounce judgment on those who deviate. It is not hard to know these people as they are very willing to make themselves known as they judge you against their version of right and wrong. There are also entire sects of Christianity that have perfected this judgement into an art form. They are more committed to the conformity of others to their religious system then they are of true Christ-likeness. They willing accept adherents regardless of their commitment to holiness while excluding those who do not adopt their religions system yet who consistently shine forth the image and nature of Christ.
In Paul's day, the chief offenders were those of the Jewish religion who constantly sought to restore Christians back to the law of Moses. However, it would no be long until Christians perpetrated the same judgment against other Christians in an attempt to secure conformity. In 190 AD Victor, the Bishop of Rome, sought to excommunicate all the eastern churches because they did not observe Easter on the same day as he did and the western churches. Fortunately, Irenaeus rebuked him, "Irenaeus, though agreeing with him on the disputed point itself, rebuked him very emphatically as a troubler of the peace of the church, and declared himself against a forced uniformity in such unessential matters." (Philip Schaff, History of the Christian Church, Section 50, Germs of the Papacy) In his defense of the Easter churches, Irenaeus noted that even Polycarp, the disciple of John, honored Easter on their set day. Far be it for the church to excommunicate one as pious as the beloved Polycarp.
Today, many people take to Facebook in a preemptive strike against those who might disagree with their choices saying, "Don't judge me!' But this is not what Paul is saying, There will always be people who will judge us, but we do not have to let their judgment control us. Paul's admonition has less to do with preventing the judgment of others as it does with not receiving the judgment of others. There are some things that simply do no matter in our walk with the Lord, such as, food, drink, festivals, observances, an holy days, even Sundays. Yes, people will always be trying to judge us according to these things, but who cares? We have been set free from these worries so why even listen to those who still try to judge us by them?
To those of the world, these things make since. They have the feel of natural religion. However, they are only the shadow of what is true religion. These people serve the shadow rather than the reality that is casting the shadow. The Greek word translated here as "substance" can also mean "body." What Paul is saying is that, those things they are so concerned about are only shadows. However, the one casting the shadow is Christ. If we serve Christ then we no longer have to worry about the shadows, but if we serve the shadows then we will never come to know Christ. Let us look up to see the body, to see Christ, and not worry about those who would judge us for doing so.