Chapter 25 is one of several passages in Isaiah that are “eschatological,” that is, it speaks of the end of time. Our section from chapter 13 to 23 has covered the nations of the earth and God’s judgment against them, culminating in chapter 24 which simply speaks of judgment against the whole earth and ends with the sovereignty of God being plainly seen (24:23). The vision in chapter 25 follows the destruction of everything and God, having destroyed even death, invites the survivors, those who trusted in Him to a grand feast.
You will find the image of this feast picked up in the New Testament. Jesus points to the end of time and says: “I say to you that many will come from the east and the west, and will take their places at the feast with Abraham, Isaac and Jacob in the kingdom of heaven” (Matthew 8:11). He uses the imagery again in Luke 12 and 14 and in Revelation 19 the image is described as a wedding feast.
Here’s the point: being invited to eat with God is a distinct honor, but only those who trust in Him will do so. All others are not just shut out of the feast, but are destroyed.