“On this mountain.” This is referring to the mountain on which Jerusalem is built and where the Temple resides (Isaiah 24:23. Cp. Isa. 2:2-3; 25:10; 27:13; Micah 4:1-2).
Isaiah 25:6-9 is about the Millennial Kingdom, when Jesus Christ rules the earth. Isaiah 25:6 actually picks up the train of thought where it left off in Isaiah 24:23. Isaiah 24 is about the Great Tribulation that precedes the Battle of Armageddon, and includes allusions to, and the idea of, Christ conquering the earth and setting up his kingdom and reigning from Jerusalem as God’s appointed king. Isaiah 24 ends with Yahweh of Armies having conquered the enemy and then reigning on Mount Zion and in Jerusalem. Then, Isaiah 25:1-5 are a poem or hymn of praise to Yahweh who has been a shelter in the storm for the godly, conquered the enemy, and is worthy of honor and praise. Isaiah 25:1-5 could be placed in a parenthesis. The flow of thought in the context continues from “Yahweh of Armies” and “Mount Zion” in Isaiah 24:23 to “Yahweh of Armies” and “this mountain” in Isaiah 25:6.
Also, once we see the connection between Isaiah 24:23 and Isaiah 25:6, we can see why Yahweh of Armies will host a magnificent feast. He has just conquered the earth and set up His kingdom, which He will rule through His Messiah, Jesus Christ. It was customary to have a huge feast when a king was inaugurated (1 Sam. 11:15; 1 Kings 1:9, 25). That the inaugural feast will be close to the beginning of the reign of the Messiah on earth is also made clear by the way Isaiah 25:6 is connected with the resurrection of the dead in Isaiah 25:7-9. It seems logical that the general sequence of end-times events near the beginning of the Millennial Kingdom of Christ on earth will be:
[For more on the prophecies in Isaiah that refer to the Millennial Kingdom, see commentary on Isa. 2:2. For more about the Millennial Kingdom, see Appendix 3, “Christ’s Future Kingdom on Earth].
“feast.” This feast will most likely be toward the beginning of Christ’s Millennial Kingdom. [For more on this feast, see commentary on Matthew 8:11].
“of choice wines.” The Hebrew text reads, “a feast of wines on the lees.” The “lees” were the sediments at the bottom of the wine, and allowing the wine to age on the lees gave the wine a deeper and richer flavor, thus the translation, “choice wines.” The NASB reads “aged wines,” and that catches the sense also. The word “lees” has been preserved in the last phrase of the verse. Leaving the wine on the lees was well known to enrich the flavor of the wine, and so allusions to it are made in several places in the Bible (Jer. 48:11; Zeph. 1:12).
“of fat meat.” More literally, “of fat” or “of the fat.” Many modern versions avoid the use of the word “fat” because so many people are health conscious, and do not like the idea of eating meat that has plenty of fat in it, but in biblical times that was not the case at all. The wording, “of the fat,” or “of fat things” or “of fat meat” communicates that this will be a feast indeed, with wonderful fatty meat and wine. But there is something else being communicated as well—the graciousness and generosity of the Host, God. According to Mosaic Law, when an animal was killed for sacrifice, God got the fat (Lev. 3:3-5, 9-11, 14-16; 4:8-10, 19, 26, 31, 35), but at this future feast, God graciously lets the people eat the meat with the fat. That there will be plenty to eat and great tasting meat with the fat is also implied in Psalm 63:5. John Oswalt (The New International Commentary on the Old Testament: Isaiah chapters 1-39) correctly comments: “To a people who did not have to worry about cholesterol, the fat portions of the meat were the best.”
“wine on the lees that has been thoroughly strained.” Leaving the wine on the lees, the sediment at the bottom of the container, gave the wine a richer flavor, but was not pleasant to drink, so the wine was strained before being consumed. Many translations say “refined,” but that is not really accurate to today’s thinking. The wine was not “refined” in any way, it was strained to get out the lees and any other thing, such as a seed, leaf, or pebble, that may have gotten into the wine in the winemaking process.