The Supper we partake of here is, among other things, a glorious foreshadowing of the great eschatological banquet. This is the time at the culmination of history, when all God’s people sit down together in the Marriage Supper of the Lamb.
In the course of history, before that time, there is a winnowing—which foreshadows those who are excluded, and there is a great gathering—foreshadowing those who are brought in, from every tribe and nation. This is that great banquet in microcosm. This is that great banquet foretold. This is that great banquet in a sign.
We see this in Matthew 8:11-12, for example. Jesus tells us that many will come from east and west, and these summoned Gentiles will sit down in the kingdom with Abraham, Isaac, and Jacob. Not only so, but the natural heirs of the kingdom, those who ought to have understood all these things, will be ejected from the banquet all, and exiled to the outer darkness.
How do you know if you are invited to that great banquet at the end of history? It is simple—by whether or not you are invited to this one. How do you know if you are invited to this one? The bread and wine are here, the gospel is here, and the invitation is declared. I have just declared it. How do you rsvp to God’s gracious invitation to sit down with Him at the Last Day? You do that, now, by eating and drinking, now, in true and living evangelical faith. So come, and welcome to Jesus Christ.