Isaiah 65:1 I am sought of them that asked not for me; I am found of them that sought me not: I said, Behold me, behold me, unto a nation that was not called by my name.
This is quoted by Paul as evidence that the gospel would go to the Nations. Whenever the New Testament interprets the Old Testament we can take that as a sure word of interpretation.
2 I have spread out my hands all the day unto a rebellious people, which walketh in a way that was not good, after their own thoughts; 3 A people that provoketh me to anger continually to my face; that sacrificeth in gardens, and burneth incense upon altars of brick; 4 Which remain among the graves, and lodge in the monuments, which eat swine's flesh, and broth of abominable things is in their vessels; 5 Which say, Stand by thyself, come not near to me; for I am holier than thou. These are a smoke in my nose, a fire that burneth all the day.
This also was interpreted by Paul. He said that the natural branches were broken off the tree and those that were wild olive branches were grafted in, referring to the nations and the gospel. Why were they broken off? He says they were broken off because of unbelief and he warns us to not be high minded but fear. If you look at these verses the Jews were high minded, that is why they were broken off, God says they were smoke in His nose. But Paul makes it clear that warning is just as much to Christians as it was to Jews.
6 Behold, it is written before me: I will not keep silence, but will recompense, even recompense into their bosom, 7 Your iniquities, and the iniquities of your fathers together, saith the Lord, which have burned incense upon the mountains, and blasphemed me upon the hills: therefore will I measure their former work into their bosom.
Therefore since Paul applied the previous warning to Christians this warning also applies to us. The OSAS crowd should provide this warning to the congregation. You can be saved from Hell by the blood of Jesus. That does not mean that going forward if you are guilty of idolatry and blasphemy that God will not recompense you. You must continually repent of sins, continually be washed by the blood, and you must repent of them and come out from their midst and be separate.
8 Thus saith the Lord, As the new wine is found in the cluster, and one saith, Destroy it not; for a blessing is in it: so will I do for my servants' sakes, that I may not destroy them all.
I would say the "new wine" is a direct reference to Pentecost and the start of the church. However, this verse applies it to Jews when He says "I may not destroy them all". The start of the church was not a destroying of any of the nations, rather it was the good news of Jesus Christ that we could be saved from our sins. However, at the same time it was a judgment on the corrupt Jewish leaders and their religion which had been filled with idolatry, arrogance and blasphemy (they said Jesus cast out demons by the prince of the demons).
9 And I will bring forth a seed out of Jacob, and out of Judah an inheritor of my mountains: and mine elect shall inherit it, and my servants shall dwell there.
Jacob is the one who is Israel. Jesus is the seed of Jacob, the name of the non transformed Israel. This word refers to a heel holder rather than a prince of God. This is a very clear reference to the covenant made with Abraham that his seed will inherit Israel and dwell there. This tells you that the covenant made to Abraham and to his seed is still going to be in effect at the end of the age.
10 And Sharon shall be a fold of flocks, and the valley of Achor a place for the herds to lie down in, for my people that have sought me.
There are two different groups within those that call themselves Jews. Peter was a Jew, Paul was a Jew, and many more. They will be saved and Isaiah 65 is part of the Old Testament, this is not a New Testament promise but an Old Testament one to those Jews who do receive Jesus.
11 But ye are they that forsake the Lord, that forget my holy mountain, that prepare a table for that troop, and that furnish the drink offering unto that number.
But there are others like the Pharisees and Sadducees who rejected the Lord. Granted the Bible is clear, the majority of Jews do reject Jesus, but then the majority of Abraham's children were not Isaac. He was in the minority.
12 Therefore will I number you to the sword, and ye shall all bow down to the slaughter: because when I called, ye did not answer; when I spake, ye did not hear; but did evil before mine eyes, and did choose that wherein I delighted not.
That is a clear reference to 70 AD, it is also a clear reference to the various persecutions of Jews in Spain, Russia, Germany, etc.
13 Therefore thus saith the Lord God, Behold, my servants shall eat, but ye shall be hungry: behold, my servants shall drink, but ye shall be thirsty: behold, my servants shall rejoice, but ye shall be ashamed: 14 Behold, my servants shall sing for joy of heart, but ye shall cry for sorrow of heart, and shall howl for vexation of spirit.
This is a reference to the Jews who reject Jesus during the church age compared to the church. But the fact that during that time God is still dealing with them proves the covenant is not over.
15 And ye shall leave your name for a curse unto my chosen: for the Lord God shall slay thee, and call his servants by another name:
Christians is that other name. This proves at some point in history the Jews will leave that name for a curse and those that truly serve Him will be called Christians. So yes, there is no future in being a Jew, but that again does not mean the covenant is over, because God is still speaking to them the path of salvation.
16 That he who blesseth himself in the earth shall bless himself in the God of truth; and he that sweareth in the earth shall swear by the God of truth; because the former troubles are forgotten, and because they are hid from mine eyes. 17 For, behold, I create new heavens and a new earth: and the former shall not be remembered, nor come into mind.
This is talking about the millennial kingdom and eternity, so yes, in eternity and in the millennial kingdom the Jewish religion will have passed away, but we are not yet in the 7,000th year.
18 But be ye glad and rejoice for ever in that which I create: for, behold, I create Jerusalem a rejoicing, and her people a joy. 19 And I will rejoice in Jerusalem, and joy in my people: and the voice of weeping shall be no more heard in her, nor the voice of crying.
Once again the reference to Jerusalem means that God has not given up the eternal covenant made with both Abraham and David. Both of which are part of the Old Covenant.
20 There shall be no more thence an infant of days, nor an old man that hath not filled his days: for the child shall die an hundred years old; but the sinner being an hundred years old shall be accursed. 21 And they shall build houses, and inhabit them; and they shall plant vineyards, and eat the fruit of them. 22 They shall not build, and another inhabit; they shall not plant, and another eat: for as the days of a tree are the days of my people, and mine elect shall long enjoy the work of their hands. 23 They shall not labour in vain, nor bring forth for trouble; for they are the seed of the blessed of the Lord, and their offspring with them. 24 And it shall come to pass, that before they call, I will answer; and while they are yet speaking, I will hear. 25 The wolf and the lamb shall feed together, and the lion shall eat straw like the bullock: and dust shall be the serpent's meat. They shall not hurt nor destroy in all my holy mountain, saith the Lord.
Once again this is a reference to all the persecution and tribulation that the Jews have gone through and their sorrow being turned to joy. Yes, it can apply to Christians too, but this word in Isaiah is part of the Old Covenant telling Jews that after going through the tribulation they will have a place in the new heaven and new earth.