It’s a prophecy not a contemporary speech
It amazes me that Isaiah the prophet prophecies concerning the crucifixion of the Messiah and numerous other details of His incarnate life, with a great deal of accuracy and yet some find it hard to believe Isaiah could prophecy about end times because those in his day were not thinking about such things. Unless Isaiah was getting his prophecies from his peers and not G-d that makes no sense.
“For who among them has stood in the council of the Lord to see and to hear his word, or who has paid attention to his word and listened?”
Jeremiah 23:18 ESV (Jeremiah is making a distinction between true prophets and false)
A divine prophecy transcends what was relevant to Isaiah. He may have been limited in conveying minute details or they may have been given to him in cryptic form but it’s not birth in his soulish imagination. This passage most definitely speaks of future events.
The way I read the text the emphasis falls on the first description of people in question
Those who sanctify and purify themselves to go into the gardens, following one in the midst,
And the second part qualifies them further by adding a descriptor. That is to say not all who fit in the second category qualify but those who fit in both most certainly do.
eating pig's flesh and the abomination and mice, shall come to an end together, declares the Lord.”
By that I simply mean that there are those who will eat pig’s flesh, the abomination and mice and yet do not follow a leader and perform certain ceremonies in sacred orchards.
Some have taken this reference of pigs, the abomination and mice and interpreted it to mean genetically modified food. The abomination being e-coli (plasmids) which are used in the process of genetic engineering to replicate and insert genes from one organism to another. E-coli is found in faeces and hence the reference of abomination being interpreted as such. Mice are a popular means of cultivating and experimenting on genetic engineering. And pigs refers to pork, or think bacon. It was an unclean animal or unclean food.
The final product in the case of bacon will contain genetic material from the e-coli and mice and obviously the pig. But it’s not limited to pigs, it’s portraying the idea of unclean food.
If we plug this back into the verse we cannot say that all who consume GMOs qualify but it is clearly referring to those in end times who have access to GMOs, if this interpretation has any validity.
Survivors or Saved
The next couple of verses are curious
“"For I know their works and their thoughts, and the time is coming to gather all nations and tongues. And they shall come and shall see my glory,”
Isaiah 66:18 ESV
It seems to be talking about Acts 2 but it might be referencing Acts 2 (which hasn’t happened according to Isaiah) and then speaks in that context to those in the end times.
“and I will set a sign among them. And from them I will send survivors to the nations, to Tarshish, Pul, and Lud, who draw the bow, to Tubal and Javan, to the coastlands far away, that have not heard my fame or seen my glory. And they shall declare my glory among the nations.”
Isaiah 66:19 ESV
Compare that with Acts 2
“Now there were dwelling in Jerusalem Jews, devout men from every nation under heaven. Parthians and Medes and Elamites and residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya belonging to Cyrene, and visitors from Rome, both Jews and proselytes, Cretans and Arabians—we hear them telling in our own tongues the mighty works of God."”
Acts 2:5, 9-11 ESV
This here mentioning the nations touches upon what I would describe the Acts of the apostles in preaching to the gentiles and that has been happening even since the first century. In Acts 2 however the nations came to them but afterwards the saved go to the nations which was in fact Jesus’ mandate
I want to focus on survivors. The word is curious to me because while it can be translated as such it has a more primitive meaning to deliver or escape. To be saved. If I replace survivors with saved then it’s saying He will send the saved to the nations, or the Christians to perform signs and wonders and therefore the gospel.
“And they shall bring all your brothers from all the nations as an offering to the Lord, on horses and in chariots and in litters and on mules and on dromedaries, to my holy mountain Jerusalem, says the Lord, just as the Israelites bring their grain offering in a clean vessel to the house of the Lord.”
Isaiah 66:20 ESV
When I read this verse I think the redemption of Efraim the ten lost tribes who have intermingled with the nations and are restored as per Romans 7 and John 1:13 by the incorruptible seed of the Word. That is the Church made up of gentiles and the Northern ten tribes, while Judah or the Jews refuse to come into the banquet of the prodigal son (but eventually they will). That’s when Paul would say “and all of Israel will be saved”. But that’s a whole different subject and it isn’t mainstream either.
And finally it clearly speaks of a new heaven and a new earth.
“"For as the new heavens and the new earth that I make shall remain before me, says the Lord, so shall your offspring and your name remain.”
Isaiah 66:22 ESV
Again the idea that all of Israel will be saved.
And if anyone doubts that Efraim who was given a certificate of divorce was still on G-d’s heart and He wanted Efraim back
“How can I give you up, O Ephraim? How can I hand you over, O Israel? How can I make you like Admah? How can I treat you like Zeboiim? My heart recoils within me; my compassion grows warm and tender.”
Hosea 11:8 ESV
“Yet the number of the children of Israel shall be like the sand of the sea, which cannot be measured or numbered. And in the place where it was said to them,** "You are not my people," it shall be said to them, "Children of the living G-d." **And the children of Judah and the children of Israel shall be gathered together, and they shall appoint for themselves one head. And they shall go up from the land, for great shall be the day of Jezreel.”
Hosea 1:10-11 ESV