Isaiah's Reminder: Remember the Covenant with David
After the rich and free banquet of YHWH, then the people are called to listen and come, because YHWH is about to reestablish the covenant made so long ago with God's special witness, the great David, he who was "leader and commander for the peoples" (Is. 55:4). That nearly 500-year-old promise made to David that the covenant with YHWH would never end (2 Sam. 7) is now reinstituted for the exiles, for those who have nearly forgotten what God had promised, who need a reminder of past promises out of which they must live.
And once they remember the covenant and begin to recapture its power for themselves, they "shall call nations that you do not know, and nations that do not know you will run to you, because of YHWH your God, the Holy One of Israel, because God has glorified you" (Is. 55:5). Isaiah promises the exiles that their task is to be a "light to the nations," a light so bright that nations they do not even know, along with nations that have never heard of them, will come running to gain a community that they never knew they needed and desired. Isaiah promises that with the renewal of YHWH's covenant the whole world will become new! New communities of nations and peoples will form around the reformed nation of Israel.
A Light to the Nations? Yes, God Really Is That Good!
One can only imagine how ridiculous all of this high-flown talk was to the exiles in Babylon. Who are you kidding, Isaiah? If by some magic act we are able to return to our homeland, just how do you imagine that we will be able to create some sort of new community with peoples we do not even know and who do not know us? And here is Isaiah's answer to that question and his answer to our questions when we imagine that God really cannot do anything new for us:
My thoughts are not your thoughts, nor are your ways my ways, says YHWH. Just as the skies are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts (Is. 55:8-9).
Our human thoughts have a very difficult time thinking largely enough to imagine how the world can become new. But God can and bids us to higher thought than we can ever do by ourselves. And that is the gospel of II-Isaiah. And that is the gospel, the good news of God. With this God, all things are finally possible.