This scripture is quoted by nearly everyone in an attempt to prove that Paul did away with the Sabbath keeping, Holy Day observance, clean and unclean meats. The truth of the matter is the real meaning of these verses is that Christians should not let people arbitrarily judge their conduct. Only the Church (Col. 1:18)-"the body of Christ" (2:17)-can do this.
if you take note of the context of Pauls letter, it is with regard to new gentile christians and their relation to the mosaic laws. Paul was informing gentile christians that they had no need to adhere to those laws.
'let no man judge you' means no one including other christians. Paul repeated this counsel to the Roman congregation
Romans 14:2
One [man] has faith to eat everything, but the [man] who is weak eats vegetables. 3 Let the one eating not look down on the one not eating, and let the one not eating not judge the one eating, for God has welcomed that one. 4 Who are you to judge the house servant of another? To his own master he stands or falls
James, if you want to observe the sabbath then by all means you can observe it. But you cannot judge those who do not observe it as disobedient or faithless or whatever your complaint is against them. Christians need only observe the express commands as laid down by the apostles...and sabbath keeping is not one of them. Here they are as a reminder:
Acts 15:19-20
Hence my decision is not to trouble those from the nations who are turning to God, 20 but to write them to abstain from things polluted by idols and from fornication and from what is strangled and from blood
The Colossians were Gentiles. They had never known God's Way, and had not previously kept His Sabbaths. In no way do these scriptures do away with God's Laws or Sabbaths which Paul himself kept! The truth is the Colossians were being criticized by unconverted Gentiles because they were keeping the Sabbath and Holy Days!
that is actually quite incorrect. The situation was that some jewish christians were telling the new gentile christians that they had to observe the mosaic laws. The issue was addressed by the Apostles in the Jerusalem congregation and the letters of Paul that went out to the new congregations, including colossians, were directly addressing the issue. It wasnt the people in the world who were criticizing them, it was jewish christians.
Acts 15:1-11
And certain men came down from Ju‧de′a and began to teach the brothers: “Unless YOU get circumcised according to the custom of Moses, YOU cannot be saved.” 2 But when there had occurred no little dissension and disputing by Paul and Bar′na‧bas with them, they arranged for Paul and Bar′na‧bas and some others of them to go up to the apostles and older men in Jerusalem regarding this dispute... 4 On arriving in Jerusalem they were kindly received by the congregation and the apostles and the older men, and they recounted the many things God had done by means of them. 5 Yet, some of those of the sect of the Pharisees that had believed rose up from their seats and said: “It is necessary to circumcise them and charge them to observe the law of Moses.” 6 And the apostles and the older men gathered together to see about this affair.
The conclusion that was reached by the Apostles and older men in Jerusalem was that if the Gentiles were being saved by their faith, and not by their adherence to the Mosaic laws, then so could the jewish christians be saved in the same way:
7 Peter rose and said to them: “Men, brothers, YOU well know that from early days God made the choice among YOU that through my mouth people of the nations should hear the word of the good news and believe; 8 and God, who knows the heart, bore witness by giving them the holy spirit, just as he did to us also. 9 And he made no distinction at all between us and them, but purified their hearts by faith. 10 Now, therefore, why are YOU making a test of God by imposing upon the neck of the disciples a yoke that neither our forefathers nor we were capable of bearing? 11 On the contrary, we trust to get saved through the undeserved kindness of the Lord Jesus in the same way as those people also.
Then James, the brother of Jesus also rose and gave his opinion on the matter, he said that the gentile were being added from among the nations and the only mosaic law requirements for them is that they abstain from idols, fornication, strangled foods and blood:
13 After they quit speaking, James answered, saying: “Men, brothers, hear me. 14 Sym′e‧on has related thoroughly how God for the first time turned his attention to the nations to take out of them a people for his name. 15 And with this the words of the Prophets agree, just as it is written, 16 ‘After these things I shall return and rebuild the booth of David that is fallen down; and I shall rebuild its ruins and erect it again, 17 in order that those who remain of the men may earnestly seek Jehovah, together with people of all the nations, people who are called by my name, says Jehovah, who is doing these things, 18 known from of old.’ 19 Hence my decision is not to trouble those from the nations who are turning to God, 20 but to write them to abstain from things polluted by idols and from fornication and from what is strangled and from blood.
After this decision was reached, the apostles wrote a letter for Paul and Baranabas to take to the many new congregations and give them the direction as was unanimously decided upon. This is the contents of the letter that was delivered to the gentile congregations:
“The apostles and the older men, brothers, to those brothers in Antioch and Syria and Ci‧li′cia who are from the nations: Greetings! 24 Since we have heard that some from among us have caused YOU trouble with speeches, trying to subvert YOUR souls, although we did not give them any instructions, 25 we have come to a unanimous accord and have favored choosing men to send to YOU together with our loved ones, Bar′na‧bas and Paul, 26 men that have delivered up their souls for the name of our Lord Jesus Christ. 27 We are therefore dispatching Judas and Silas, that they also may report the same things by word. 28 For the holy spirit and we ourselves have favored adding no further burden to YOU, except these necessary things, 29 to keep abstaining from things sacrificed to idols and from blood and from things strangled and from fornication. If YOU carefully keep yourselves from these things, YOU will prosper."
It is the Apostles who determined that sabbath keeping was not a requirement for christians. They came to this decision because they saw that God was bringing in gentiles who had never practiced the mosaic laws....yet God was granting them salvation and pouring his holy spirit on them. This proved to the Apostles that obedience to the mosaic law was not something God required of people. But like I said, if YOU want to observe the sabbath, then im sure there would be not problem with you doing that...just remember Jesus words "with what judgment you are judging, you will be judged"