Absolutely correct! Notice what Paul did...
Act 17:2 And Paul, as his manner was, went in unto them, and three sabbath days reasoned with them out of the scriptures,
He was reasoning with Gentiles. Why didn't he tell them they did not have to come together on the Sabbath? Because nothing changed...
Mal 3:6 For I am the LORD, I change not; therefore ye sons of Jacob are not consumed.
Heb 13:8 Jesus Christ the same yesterday, and to day, and for ever.
Be aware that john832 is an Armstrongite, following the teachings of Herbert Armstrong. I was an Armstrongite for 10 years so I am intimately familiar with their teachings. It is a cultic movement that teaches they will be fully God in the resurrection, with the same powers as God the Father and Jesus Christ. In addition, they consider Sunday observing Christians to be unbelievers, under the Mark of the Beast.
john832 made remarks that indicated his disapproval with my exodus from Armstrongism on my testimony, so that's how I know his doctrinal perspective.
Regarding his remarks on this topic:
Paul evangelized Jews in the synagogue. It was his pattern to go to the synagogue first to evangelize Jews, and worked from there until he was kicked out. Eight of the 9 references to the Sabbath related to Paul are evangelism in the synagogues, and the ninth one relates to a riverside meeting of unconverted Jewish women, one of which was Lydia who was saved in this encounter.
You will find no records of church meetings on Sabbath in the New Testament after the resurrection...they were all meetings in the synagogue for evangelistic purposes. Some Jewish believers may have continued to attend Synagogue after this evangelism, because the scrolls were housed there. In addition, there would be no issue if Jewish believers continued to observe elements of their faith..they observed even physical circumcision after the resurrection (Acts 21). They, along with Gentile believers, may have continued to attend Synagogue to hear the Scriptures read. As I said, ready access to the scrolls of the Old Testament were available there.
You WILL find evidence of church meetings on the first day of the week in the New Testament after the resurrection. You won't find any references of non-synagogue meetings on the Sabbath, though.
The pattern seems to be that they attended synagogue to hear the Scriptures read (the scrolls were housed there), and then discussed them from a Christian standpoint on Sunday, as well as practicing communion amongst themselves on the first day of the week. And, no, I do not accept Armstrong's explanation that "breaking bread" only relates to eating food and not communion anymore. So, you can save the explanation in that regard.
Regarding God changing, no he doesn't change..however to claim that his manner of dealing with people never changed is fallacious. We know that animal sacrifices and physical circumcision are no longer applicable, so your reason for referring to this verse is not sound. In the same regard, the Sabbath, festivals and clean/unclean laws are no longer applicable (Colossians 2:16-17, Mark 7, Romans 14) despite the Armstrongite attempts to prove otherwise. Using the Scripture to make an inference that God never changes his way of dealing with people, if you were consistent, would mean that the entire Mosaic Covenant is still in effect. Instead, you select 3 or 4 elements that your apostle/prophet deemed to be in effect and fixate on those.
In addition, a common claim is that Holy Days were observed by the Gentile churches, such as in I Corinthians 5, so this proves the continuing requirement for both Jews and Gentiles to observe festivals. Those who make such claims don't understand that the Gentile churches also had a significant population of Jews, as Jews migrated outside of Palestine for economic opportunities and due to earlier persecutions related to Antiochus Epiphanes. In addition, Paul's reference may have been metaphorical and not literal. Either way, there is no compelling proof in these references that the Sabbath and festivals were continued requirements. Again, there were big assumptions made by Armstrongites relating to their claims.
One must also remember that Armstrong also made blasphemous claims like saying that the redeemed will be fully God in the resurrection, with the same powers as the Father and Son. These claims are based largely upon his faulty understanding of the Triune nature of God, biblical regeneration, and the bodily resurrection. So, the entire system is messed up. One doctrinal error can have a cascade effect which affect several doctrines, and you see that plainly in Armstrongism.
No man who believes he is going to be fully God in the resurrection with his own planet ruling over humans is capable of teaching Christianity to anyone, and Armstrongites believe this, besides teaching that everyone else is spiritually blinded and unsaved other than themselves, including all Sunday observing Christians. Other followers of Christ, outside of Armstrongism, are considered "so-called Christians" following a "counterfeit Christianity" teaching a "false gospel" and are of the "synagogue of Satan", if they are a Sunday observing Christian.
The Armstrongite view of Revelation 17 is that the Roman Catholic church is the "great prostitute" and Sunday observing Protestants are the "harlot daughters" of the great prostitute, and are under the Mark of the Beast due to Sunday observance.
Restored Church of God, Philadelphia Church of God, Living Church of God, and United Church of God are associated with Armstrongism. These organizations have podcasts and TV programs teaching Armstrong's doctrines. I was involved with them for a decade. Big waste of time. I could have spent those years going to seminary or something, instead I spend them listening to cultic doctrines.
If you are persuaded that Sabbath/festival/clean meat law observances are something you should do, find a Jews for Jesus congregation or a sound organization that practices these things. Don't get involved with Armstrongism or other cultic groups. I think some Messianic Jew organizations are also sound, although I'd compare their teachings with the essentials of the Christian faith first. Some Messianic Jews deny things like the deity of Christ, Trinity doctrine, and the writings of Paul.
I'd suggest reading Sabbath in Christ by Dale Ratzlaff first, though. Dale is a fourth generation ex Seventh Day Adventist and understands the basic issues related to these topics very well.