Thank you my dear friend for this excellent question. The verse to which you refer is as follows: “They that sanctify themselves, and purify themselves in the gardens behind one tree in the midst, eating swine’s flesh, and the abomination, and the mouse, shall be consumed together, saith the LORD”. This verse is the prophetic Word of the Lord through Isaiah speaking to the ungodly of God’s people Israel (Judah), warning them of the judgment which will come upon Judah for their having abandoned the proper worship of God, and for following after false gods. This is the short answer to your question. However, God’s Word in this chapter, I believe, pertains to both the judgments in Isaiah’s day at the hands of Babylon, and as well to more comprehensive judgments to occur in the end times, when the Lord Jesus returns to the earth the second time in glory and power. In order to better understand this verse, we must look at the spiritual condition of Israel at the time of Isaiah. Recall that the northern kingdom of Israel had already been judged by the LORD, the people having been removed by the Assyrians due to Israel’s long history of ungodly kings which had led the people to sin by following false gods. Actually, much of the book of Isaiah spells out the declining spiritual condition of the southern kingdom, Judah, which had gradually declined spiritually in the generations after the reign of king David. By the time of Isaiah, the Judean kings had fallen away from the Lord, and the people of Judah were committing great abominations against their God, even in His temple. They continued their sacrifices, but their hearts and their practices were utterly sinful in God’s sight.  Since they continued in sin, their sacrifices were repugnant to the LORD, and the righteous God would therefore need to judge Judah due to their infidelity to the LORD (Isaiah 65:2-7; 66:14-16). We read in Isaiah 66:15-16, “For, behold, the LORD will come with fire, and with His chariots like a whirlwind, to render His anger with fury, and His rebuke with flames of fire. For by fire and by His sword will the LORD plead with all flesh: and the slain of the LORD shall be many”.

Now, if you consider both chapters 65 and 66 of Isaiah together, you’ll see a review of the sins of many of the people of Judah spelled out, along with the prediction of the judgment of God’s people, but also the ultimate restoration and blessing of a “faithful remnant”. I believe that the most immediate application of this prophesy of judgment was already occurring at the time of Isaiah, when the children of Judah were being carried away by the Babylonians, and Jerusalem and the temple were destroyed utterly; but, I believe also that much of what we see in these two chapters refers clearly to the end times when the judgments will be executed in their fulness with the second coming of the Lord Jesus to the earth. The coming of the Christ in judgment is predicted (see Isaiah 66:5; Joel 2:31; Zechariah 14:1-4; Malachi 3:1,2). Thus, here the focus shifts squarely to the end times when God will pour out His righteous wrath on those in Israel who continued in their sinful ways, and as well, on all the nations of the world who would not honor God (Isaiah 65:11-15). So, the Lord will return and put down all the ungodly; then, after the enemies are defeated and the ungodly are judged, Christ Jesus will then mount David’s throne and will set up the millennial kingdom. In that day, the faithful of Israel will be returned to their land (Israel), and there, the promises made to Abraham of land, seed and blessing will be fully realized, and in perpetuity. The Gentiles who will believe the message of God’s glory in that day will come to Jerusalem to worship the Great King, the Lord Jesus Christ. All of this is brought out in Isaiah 66! I also think it is exciting to note that Isaiah 53 is the prophetic voice of the faithful remnant of Israel when they have finally received their King. In that day, the faithful remnant will inherit the land in peace and prosperity, with Christ as their King, and this is as certain as the new heavens and the new earth. We read in Isaiah 66:22: “For as the new heavens and the new earth, which I will make, shall remain before Me, saith the LORD, so shall your seed and your name remain”.

MacDonald in his Bible Commentary on Isaiah 66:10-17 reads as follows: “The day of Israel’s restoration will be a time of great rejoicing in Jerusalem. All…who love her and who have wept with her will share in the ecstasy and jubilation of that moment. Enriched by the glory of the Gentiles, she in turn will give prosperity, nourishment, comfort, and rejuvenation to all who come to her. Then it will be obvious to all that Jehovah is committed to the welfare of His own and to the punishment of His enemies. The Lord’s Second Coming will mean the unleashing of His fiery indignation against all idolaters and rebels. He sees them going through ceremonies to make themselves ritually clean, only to engage in the most abominable idolatrous practices.”  (SF)  (522.4)