Actually they do the very opposite. But the argument is complex and detailed so I will sketch the argument here. I would sugest that you take sometime to actually read up on the issue. I know someone who argues that the Scriptures teach that Christians are not to celebrate the Lord's supper! His proof is 1 Corinthians 11:20, "When ye come together therefore into one place, this is not to eat the Lord's supper." The verse in contexts actually teaches the very opposite but anyway....Let us place the verses that Paul wrote in Colossians into a context.
"So let no one judge you in food or in drink, or regarding a festival or a new moon or sabbaths, which are a shadow of things to come, but the substance is of Christ."
A similar verse can be found in Paul's epistle to the Romans,
"One person esteems one day above another; another esteems every day alike. Let each be fully convinced in his own mind. He who observes the day, observes it to the Lord; and he who does not observe the day, to the Lord he does not observe it. He who eats, eats to the Lord, for he gives God thanks; and he who does not eat, to the Lord he does not eat, and gives God thanks."
There is then a context to Paul's saying these and the context is that of Jewish Christians demanding that Gentile Christians keep Jewish festivals new moons and sabbaths. That is the context. The question therefore is to ask what Paul meant by "a festival or a new moon or sabbaths".
The answer is found in the Old Testament. The easiest verse to see my point from is 2 Chronicles 8:13
"Even after a certain rate every day, offering according to the commandment of Moses, on the sabbaths, and on the new moons, and on the solemn feasts, three times in the year, even in the feast of unleavened bread, and in the feast of weeks, and in the feast of tabernacles."
Granted the order of the terms is reversed but that is not relevant. What is important is to note the link between the phrase and the Mosaic worship. The link is of course Leviticus 23. Here we find Moses declaring to the children of Israel the feasts of the LORD. We find the Passover and Unleavened Bread, the Feast of Firstfruits, the Feast of Weeks, the Feast of Trumpets, the Day of Atonement and the Feast of Tabernacles. However the reference is far wider;
holyday; or feast, such as the feast of the passover, the feast of tabernacles, and the feast of Pentecost; which were three grand festivals, at which all the Jewish males were obliged to appear before the Lord; but were never binding upon the Gentiles, and were what the Christians under the Gospel dispensation had nothing to do with, and even believing Jews were freed from them, as having had their accomplishment in Christ; and therefore were not to be imposed upon them, or they condemned for the neglect of them.
the new moon; which the Jews were obliged to observe, by attending religious worship, and offering sacrifices; see
Numbers 28:11 "And in the beginnings of your months ye shall offer a burnt offering unto the LORD; two young bullocks, and one ram, seven lambs of the first year without spot"
2 Kings 4:23 "So he said, 'Why are you going to him today? It is neither the New Moon nor the Sabbath.' And she said, 'It is well.'"
the sabbath days, or "sabbaths"; meaning the jubilee sabbath, which was one year in fifty; and the sabbath of the land, which was one year in seven; and the seventh day sabbath, and some copies read in the singular number, "or of the sabbath"; which were all peculiar to the Jews, were never binding on the Gentiles, and to which believers in Christ, be they who they will, are by no means obliged; nor ought they to observe them, the one any more than the other; and should they be imposed upon them, they ought to reject them; and should they be judged, censured, and condemned, for so doing, they ought not to mind it.
Paul's reference then was not to a weekly sabbath of any sorts. Indeed, this had originated at creation, was kept by the patriarchs, was kept by the Israelites. The sabbaths, new moons, and the solemn feasts were added to the religious calendar of Israel. These were part of the ceremonial worship under the Old Covenant. These sabbaths, new moons, and the solemn feasts prefigured the work of Christ and so were fulfilled in him. That was why the Gentile Christians did not have to keep Jewish ceremonies. These ceremonies were temporary, part of the ceremonial law of Israel, the weekly sabbath is however moral just like marriage. Marriage and the sabbath are both creation ordinances. Both are moral, both continue until Christ comes again.