According to Colossians, there appears to be some disagreement amongst the first century church on whether to keep the Sabbath:
Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day.
Did the first century church keep the Sabbath?
And if so which day was it on? The Jewish Saturday or the new Christian Sunday?
The writings of the early Christians make it clear that Christians abandoned the Jewish custom of worship on the Sabbath (seventh day) and instead held the first day, which they called the Lord's Day, to be the sacred day of worship. One of the simplest explanations on the subject comes from Tertullian, around 200 AD:
But why is it, you ask, that we gather on the Lord's Day to celebrate our solemnities? Because that was the way the Apostles also did.
-- De Fuga in Persecutione, XIV: 11
This was not an innovation of the second century AD, as a full century earlier, (101 AD,) we find Ignatius saying:
Those who were brought up in the ancient order of things have come to the possession of a new hope, no longer observing the Sabbath, but living in the observance of the Lord's day on which our life was sprung by him and his death.
-- Epistle to the Magnesians, Chapter 9
And just in case there is any confusion as to the identity of the Lord's Day, we can turn to Justin Martyr. (140 AD)
And on the day which is called Sunday there is an assembly in the same place of all who live in cities or in country districts; and the records of the apostles, or the writings of the prophets, are read as long as we have time.
...
Sunday is the day on which we all hold our common assembly, because it is the day on which God, when he changed the darkness and matter, made the world; and Jesus Christ our Savior on the same day rose from the dead.
-- Apologies 1:67
And again from Justin Martyr, we see that Christians did not keep the Jewish holy days:
We neither accord with the Jews in their peculiarities in regard to food nor in their sacred days.
-- Apologies Sec. 21
So yes, it's clear from the historical record that the first-century Christians, such as Ignatius, had organized worship meetings on the Lord's Day (Sunday), and that they did not consider observance of the Jewish Sabbath important, it having been fulfilled by Christ with the rest of the Law of Moses.
The first Christians were Jewish, so they naturally observed the Sabbath on Saturday--just like they always had. They worshiped the God of Abraham, Isaac, and Jacob--just like they always had, but they did so with the realization that the God of Abraham, Isaac, and Jacob and visited them, that is, that Jesus the Messiah, the eternal Son of God had become a man, had been crucified, buried and rose again on the third day, that is, on Sunday.
It also appears that they began to observe the first day of the week as Jewish believers in order to honor the day of the resurrection.
On the first day of every week, each of you is to put something aside and store it up, as he may prosper, so that there will be no collecting when I come. 1 Corinthians 16:2 ESV
Gentiles were never required to become Jewish in order to follow Jesus. They were not required to be circumcised or to observe the Jewish Sabbath or refrain from eating pork--or any of the covenant laws of Israel.
Still, Paul and Peter continued to attend Sabbath days in the synagogue and to proclaim Jesus.
The verse immediately after the one you cited states this:
These are a shadow of the things to come, but the substance belongs to Christ. Colossians 2:17 ESV
So, Paul is stating that the New Moons, Sabbaths and all that (from the Law) were a shadow of the things that were to come. The reality is found in Jesus. Therefore, if Gentile believers did not do all of these things, they should not be concerned with the Judaizers or any who would criticize them for that.
As Gentile believers in Jesus the Messiah, it seems appropriate to honor the day of resurrection, following the pattern set forth by the early church.
Still, if you happen to celebrate and worship Jesus on the wrong day, I'm sure that's alright. In fact, we should probably worship Him every day of every week, and certainly not just one day a week.
I see you have all agreed on the same point that Sunday became the Lord's Day, according to my understanding of the Holy Scriptures this is untrue. Jesus called Himself the Lord of the Sabbath which makes the Saturday the Lord's Day (Matthew 12:1-14). Jesus Christ kept the Sabbath, Apostles kept the Sabbath.(Acts 18:4 And he reasoned in the synagogue every Sabbath, and persuaded the Jews and the Greeks). If you understand this verse Paul was in a foreign land which is Corinth. He kept the Sabbath and reasoned in the synagogue 'every' Sabbath. He even stayed the for 18 months (Acts 18:11) attending on the holy convocation called Sabbath.
With your use of Colossians 2:17, 'shadows of the things to come', why would God transfer the Sabbath to Sunday when He will again restore it in future? We will have to Sabbath as it one of the thing to come. You confuse church meeting that took place on Sunday to collect the things that were to be sent to help other Christians (1 Corinthians 16:2). That was to be done on Sunday so that 'there would be no collection' [when] Paul comes. When would Paul come, on Sunday or on Sabbath? This does not mean they would assembly for worship on Sunday. In the Revelation again, it does not say Sunday, John was in Patmos for the Word of God and the testimony of Christ. Was John a Gentile? John the Apostle was not the Gentile, He was a Jew. So why would he refer to Sunday as a Lord's day? In the Book of Acts, it is making it clear that Paul and other Apostles still used the Seventh Day as the Sabbath, they still kept it. In another foreign land which is Antioch, we see reference of meeting in Sabbath days i.e. Acts 13:14 c.f. Acts 13:27, 42-44, 15:21, 16:13. There is no where in the Scripture we find apostles saying the First day of the week replacing the Seventh day. It is only from the traditions of man.
In Antioch, Paul went into the synagogue on the sabbath day per act13vs14.
but they went on from Perga and came to Antioch in Pisidia. And on the Sabbath day they went into the synagogue and sat down.
But in verse 16 told you why because those people were Jews living in Antioch.
So Paul stood up, and motioning with his hand said: “Men of Israel and you who fear God, listen.
In 27 Luke is telling us about in historical event
For those who live in Jerusalem and their rulers, because they did not recognize him nor understand the utterances of the prophets, which are read every Sabbath, fulfilled them by condemning him.
In 42,44 Paul preach in the synagogue last.
42 As they went out, the people begged that these things might be told them the next Sabbath. 43 And after the meeting of the synagogue broke up, many Jews and devout converts to Judaism followed Paul and Barnabas, who, as they spoke with them, urged them to continue in the grace of God.n44 The next Sabbath almost the whole city gathered to hear the word of the Lord.
I check still going on on Saturday also for 15:21 and act 20:7-12 Paul preaching on Sunday
