The only Gentiles in the synagogues on Saturdays were circumcised, devout converts to Judaism.
Once you read and understand the Scriptures about how Jesus removed this wall of separation at His death, what Paul was correcting Acts 15:1 not correcting people and teaching to disobey God and His commandments. 1Cor7:19
Jesus predicted His house of prayer on the Sabbath would be for All Nations- Jesus never destroyed His prophecies of the OT and I would also consider, in the Bible people served God and what
He said, not the other way around. The ones who didn't were the ones in rebellion to God- we can make these same mistakes.
Isa 56:6 “Also the sons of the foreigner (Gentiles)
Who join themselves to the Lord, to serve Him,
And to love the name of the Lord, to be His servants—
Everyone who keeps from defiling
the Sabbath,
And holds fast My covenant—
7
Even them I will bring to My holy mountain,
And make them joyful in My house of prayer.
Their burnt offerings and their sacrifices
Will be accepted on My altar;
For My house shall be called a house of prayer for all nations.”
8 The Lord God, who gathers the outcasts of Israel, says,
“Yet I will gather to him
Others besides those who are gathered to him.”
At the Cross Jesus took away that wall of separation of circumcision
Col 2:11 In Him you were
also circumcised with the circumcision made without hands, by putting off the body [h]of the sins of the flesh, by the circumcision of Christ, 12 buried with Him in baptism, in which you also were raised with
Him through faith in the working of God, who raised Him from the dead. 13 And you, being dead in your trespasses
and the uncircumcision of your flesh, He has made alive together with Him, having forgiven you all trespasses, 14 h
aving wiped out
the [i]handwriting of requirements that was against us, which was contrary to us. And He has taken it out of the way, having nailed it to the cross.
Eph 2:11 Therefore remember that you, o
nce Gentiles in the flesh—who are called Uncircumcision by what is called the Circumcision made in the flesh by hands— 12
that at that time you were without Christ, being aliens from the commonwealth of Israel and strangers from the covenants of promise, having no hope and without God in the world. 13 But now in Christ Jesus
you who once were far off have been brought near by the blood of Christ. 14 For He Himself is our peace, who has made both one,
and has broken down the middle wall of separation, 15 having abolished in His flesh the enmity,
that is, the law of commandments
contained in ordinances, so as to create in Himself one new man
from the two,
thus making peace, 16 and that He might reconcile them both to God
in one body through the cross, thereby putting to death the enmity. 17 And He came and preached peace to
you who were afar off and to those who were near. 18
For through Him we both have access by one Spirit to the Father. 19 Now, therefore, you are no longer strangers and foreigners, but fellow citizens with the saints and members of the household of God, 20 having been built on the foundation of the apostles and prophets, Jesus Christ Himself being the chief corner
stone, 21 in whom the whole building, being fitted together, grows into a holy temple in the Lord
Which is exactly what the LORD predicted
Isa 56:6-7 Gentiles are no longer separated from Israel and the promises of the covenant why the LORD said to keep the Sabbath and
holdfast My covenant
Isa56:6 because Gentiles are grafted into the same covenant promise made to Israel having the law of God written in their minds to do them and written in their hearts because we love God and want to keep His commandments which of course includes the 4th because God said it did so plainly
Isa56:6 Exo20:8-11 Exo20:1-17 Exo20:6 Jer 31:33 Heb8:10 2Cor3:3
Which is why
both Jews and Gentiles were in God's house of prayer keeping
every Sabbath together, just as God predicted.
Acts 13:42 42 [
n]So when the Jews went out of the synagogue
, the Gentiles begged that these words might be preached to them the next Sabbath.
Acts 13:44 On the
next Sabbath almost
the whole city came together to hear the word of God.
Why we see Sabbath-keeping was kept in every city, on every Sabbath for many many generations because this is God's written and spoken will
Psa40:8 Exo30:18 Exo20:8-11
Acts 18:4 And he reasoned in the synagogue
every Sabbath, and persuaded
both Jews and Greeks.
And the true fulfillment...
Isa 66:23 And it shall come to pass
That from one New Moon to another,
And
from one Sabbath to another,
All flesh shall come
to worship before Me,”
says the Lord.
What God predicts always comes true...His house of prayer on the Sabbath will be for
all nations. Why we see today Sabbath-keeping by millions and millions of people around the world, sadly a remnant Rev12:17 because most follow who changed God's Sabbath. Dan7:25
Sin separated man from God. We can worship God only in spirit but once Jesus comes, worship will continue back in His presence every Sabbath gathering before the LORD from one Sabbath to another. If we are so opposed to Sabbath worship now, would the God of love make people do this against their will for all eternity, I do not believe so, I believe His judgement is one of love because not everyone will be happy in a world without sin and living God's will John3:19-21