Nathan MacDonald (Not Bread Alone) argues that “The description of the feast in [Isaiah] 25.6–8 is usually taken to be of a coronation meal or a meal to celebrate YHWH's kingship. Although this idea has been related to theories of an enthronement festival in pre-exilic Israel, it is independent of those theories because the identification of YHWH as king in 24.23–5 is clear. The alternatives to YHWH’s lordship of the earth are imprisoned and punished and YHWH takes over direct rule of the earth from Zion. The meal that is attended by all peoples follows on from his assumption of universal kingship” (192).
The festive scene not only links festivity to kingship, but also specifically to judgment. MacDonald writes, “The eschatological meal in Isa. 25.6–8 is, therefore, rightly seen as a meal that celebrates YHWH’s kingship over the earth. Consequently all the nations are invited to the meal. This meal is the context for divine judgement, most especially in relation to ‘death’, which is consumed by YHWH. We must not, though, assume that the annihilation of death means judgement is absent for the peoples of the earth. . . . the heavenly powers and the earthly kings are judged and punished. Israel, on the other hand, is vindicated before all. We can conclude, then, that the table in Isaiah 25 belongs to the motif of judgement and vindication at the table, but in this case it is projected uniquely into the eschatological future” (194).
Christians believe that the feast of Isaiah 25 is our feast, our Eucharist. As in Isaiah, we celebrate a feast of wine because God has taken the throne. And as in Isaiah, the feast isn't an altogether safe place, for there are some who are sick and some who have fallen asleep because they have celebrated unworthily.