We are the people of God, and so of course He promises to feed us. We are the sheep of His pasture, and He also promises to feed us in the presence of our enemies (Ps. 23:5).
And while we are being fed, our enemies are not silent about it. While we are being fed by the Lord, we hear their commentary about what is going on. They have opinions about our food, just as we are instructed to have opinions about theirs.
While Hezekiah and his people were besieged in Jerusalem, Rabshakeh, their adversary, taunted them about their food. He said that Hezekiah (and by implication, the Lord) would only be able to provide them with the loathsome food and drink of their own bodily waste (Is. 36:16). But if they listened to him, and surrendered, they would be led to a land of “corn and wine, bread and vineyards” (Is. 36:17). He would provide them with a true feast, and there they would be able to serve a “great king, the king of Assyria (Is. 36:4).”
God counters with a promise to Hezekiah (Is. 37:30) that they will be fed, and Sennacherib will come to nothing. There is a two-fold refutation. What they say about our table is false, and will be shown to be false. Secondly, what they claim about their promised food is also false. Why spend money for bread that is not bread (Is. 55:1-2). Come, let your soul delight in fatness.
The great king, the king of Assyria, was about to encounter an epic disaster, and that would be crowned with the indignity of being murdered by his own son. This, in contrast with the great king of Heaven and earth, who gave up His Son, who willingly laid down His life for us, that we might have the food and drink of everlasting life. And here it is now, the bread and wine of true grace.
Come, and welcome, to Jesus Christ.