You didn't read the text carefully.
It is "those that escape of them"... which is a remnant of "all nations and tongues". These are Gentiles!
The Gentiles shall "bring all your brethren for an offering unto the Lord out of all nations".
This is the EXACT Scripture you asked for!!
I read it carefully, we just have a different lens for viewing scripture. Verse 18, to me, is the key to understanding the prophecy. God was soon going to breakdown the barrier between the Jews and gentiles. The old covenant was just with the people of Israel, but soon God would covenant with all peoples, nations, and tongues under the new covenant. Under Christ, Jews and Gentiles are now one (Galatians 3:28). Jews and Gentiles, under Christ, are brothers and sisters.
Isa 66:18-20
For I know their works and their thoughts:
it shall come, that
I will gather all nations and tongues; and they shall come, and see my glory. 19 And I will set a sign among them
(Jews and gentiles), and I will send those that escape
(Jews) of them
(gentiles) unto the nations, to Tarshish, Pul, and Lud, that draw the bow, to Tubal, and Javan, to the isles afar off, that have not heard my fame
(gentiles), neither have seen my glory
(gentiles); and they
(Jews) shall declare my glory among the Gentiles. 20
And they shall bring all your brethren for an offering unto the Lord out of all nations upon horses, and in chariots, and in litters, and upon mules, and upon swift beasts, to my holy mountain Jerusalem, saith the Lord, as the children of Israel bring an offering in a clean vessel into the house of the Lord.
Vs 20 parallels:
They shall bring = children of Israel shall bring
Your brethren, out of the nations, for an offering= an offering in a clean vessel
Unto to the Lord = to house of the Lord
Additionally, We have Hebrews 12:22 that tells us some important information on Mount Zion and Jerusalem
But you have come to
Mount Zion and to the city of the living God, the heavenly Jerusalem, and to innumerable angels in festal gathering, 23 and to the assembly of the first-born who are enrolled in heaven, and to a judge who is God of all, and to the spirits of just men made perfect, 24
and to Jesus, the mediator of a new covenant, and to the sprinkled blood that speaks more graciously than the blood of Abel.
AGAIN, you are missing the point. The prophecy states it is those that BROKE the covenant, "the house of Israel", that will be made "My People"! This process requires God's law being "put" in their inward parts ... not this only happens to those that KEPT God's law. Granted, they DO have to accept this teaching, but they still REQUIRE the teaching.
There is no point to be missed, you stated the remnant broke the covenant but provided no scripture that says THE REMNANT, specifically, broke the covenant.
Jer 31:32-33 Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt;
which my covenant they brake, although I was an husband unto them, saith the Lord: 33 But this shall be the covenant that I will make with the house of Israel; After those days, saith the Lord,
I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people
Let's look at Hebrews 10:11-18, which discusses the fulfillment of Jer 31:32-33
And every priest stands daily at his service, offering repeatedly the same sacrifices, which can never take away sins. 12 But when Christ had offered for all time a single sacrifice for sins,
he sat down at the right hand of God, 13 then to wait until his enemies should be made a stool for his feet. 14 For by a single offering he has perfected for all time those who are sanctified. 15 And the Holy Spirit also bears witness to us; for after saying,
16 “
This is the covenant that I will make with them
after those days, says the Lord:
I will put my laws on their hearts,
and write them on their minds,”
17 then he adds
,“I will remember their sins and their misdeeds no more.”
18
Where there is forgiveness of these, there is no longer any offering for sin.
This is the new covenant. It was made with the Jew first, and then the Gentile
Romans 2:14
(Indeed, when Gentiles, who do not have the law, do by nature things required by the law, they are a law for themselves, even though they do not have the law.
15They show that the requirements of the law are written on their hearts, their consciences also bearing witness, and their thoughts sometimes accusing them and at other times even defending them.)