Is 56:6-8 gentiles (not Jews) are specifically singled out for Sabbath keeping
Any gentile that commits to that covenant is a Jew - Ex 12:48. .
Not true. They are gentiles. "Foreigners". And it does not matter where they live according to Isaiah 56.
“Also
the foreigners who
join themselves to the Lord,
To minister to Him, and to love the name of the Lord,
To be His servants,
every one who keeps from profaning the Sabbath
And holds fast My covenant;
7 Even those I will bring to My holy mountain
And make them joyful in
My house of prayer.
Their burnt offerings and their sacrifices will be acceptable on My altar;
For
My house will be called a house of prayer for all the nations.”
Ex 12:48 does NOT say "anyone who keeps from profaning the Sabbath is a Jew". And we all know it.
Ex 12
48 But if a stranger sojourns with you, and
celebrates the Passover to the Lord, let all his males be circumcised, and then let him come near to celebrate it; and he shall be like a native of the land. But no uncircumcised person may eat of it.
Nothing at all there about the weekly Sabbath - the Sabbath commandment. As we all can see clearly.
So it is gentiles .. foreigners "all nations" in Isaiah 56 -- not circumcised passover-keeping Jews.
And it is foreigners - "god fearers" in Acts 14 - gentiles that are worshiping in the Synagogue "Sabbath after Sabbath" and asking for MORE Gospel preaching "NEXT Sabbath" when the "entire town" shows up... still gentiles.
Thus it is that gentiles show up in Acts 17:1-4 and in Acts 18:4-6 Sabbath after Sabbath in the synagogue for Gospel preaching.
Not if they join the covenant. They're to be treated as one in the land.
The text you reference only speaks about Passover and circumcision ... nothing at all in it about gentiles in all nations and the weekly Sabbath.
By contrast - the texts I point to - do reference gentiles in all nations and the weekly Sabbath. and we see them not only in Isaiah 56 but also in the NT - in
Acts 13, Acts 17, Acts 18 -- Sabbath after Sabbath... gentiles, not Jews
I don't live in Israel and therefore I'm not the foreigner of Isa 56.
Isaiah 56 does not say the foreigner lives in Israel.
Those gentiles keeping Sabbath in Acts 13, Acts 17, Acts 18 were not in Israel, were not circumcised, were not Jews.
Read your quotations again.
Isaiah 56:7
...Their burnt offerings and their sacrifices will be acceptable on My altar...
That is a requirement under the old covenant.
You are conflating two different things.
1. The liturgy of worship - before the cross vs after (no matter if the one worshiping is a Jew or gentile)
2. the requirement of a gentile worshiper to ALSO become a circumcised Jew IF they want to also observe the Passover.
Details matter.
Animal sacrifices needed before the cross -- no matter if one was Jew or gentile.
Gentiles needed to be circumcised if they wanted to go to the temple and keep Passover -- no matter if it was before the cross or after.
But
none of those gentiles in Acts 13, `17, 18 worshiping in the synagogues every Sabbath are Jews - rather they are called "God fearing gentiles" -- they keep Sabbath but they are not circumcised Jews.
Bible details matter. Nice try though.
Your so confused.
A Gentile can never become a Jew, though a Gentile can convert to Judaism.
On the contrary - "god fearing gentiles"
"God-fearers (Greek: φοβούμενος τὸν Θεόν, Phoboumenos ton Theon) or
God-worshipers (Greek: θεοσεβής, Theosebes) were a numerous class of
gentile sympathizers to Hellenistic Judaism, which observed certain Jewish religious rites and traditions
without becoming full converts to Judaism."
Full converts were not called gentiles and could enter the temple.
Ex 12
48 But if a stranger sojourns with you, and celebrates the Passover to the Lord, let all his males be circumcised, and then let him come near to celebrate it;
and he shall be like a native of the land. But no uncircumcised person may eat of it
A Gentile cannot become a priest in the temple
A Jew could not become a priest either - they had to be Levites and in fact descendant from Aaron.