Here the voice of God mimics the voice of the street vendor inviting passersby to "come, buy and eat." Hawkers and vendors were no doubt common on the streets of the cities and villages of biblical Israel--as they still are everywhere in the world, especially where established shopping areas are less frequent or not accessible to those without sufficient funds. But in this text, funds do not matter, because the food, the bread, the milk, and the wine are free. God is giving it all away.
The menu here is metaphorical. God offers the restoration of Israel, the rebuilding of Jerusalem, the making of all things new. Why, wonders God, would anyone settle for less--which, in this book, might include worship of the Babylonian idols and the imagined security of remaining in exile.
Early on, God made an everlasting promise to David: "Your house and your kingdom shall be made sure forever before me; your throne shall be established forever" (2 Samuel 7:16). This became the basis for Israel's hope in a righteous king, a messiah (anointed one) who would usher in the fullness of God's kingdom. In exile, that hope was shattered: the temple, the palace, the royal city, and the line of David had been destroyed. But, says the prophet, all is not lost; indeed, everything is gained. Now the covenant with David is extended to all the people; the promise has been democratized--a step similar to the one taken when the New Testament calls all believers a "royal priesthood" (1 Peter 2:9). In both Old Testament and New, the gift of God's covenant promise is not simply something to be treasured for the recipients; it turns them into "a witness to the peoples" (v. 4). God opens the door more fully to Israel in order to open the door more fully to the world.
55Ho, everyone who thirsts,
come to the waters;
and you that have no money,
come, buy and eat!
Come, buy wine and milk
without money and without price.
2 Why do you spend your money for that which is not bread,
and your labour for that which does not satisfy?
Listen carefully to me, and eat what is good,
and delight yourselves in rich food.
3 Incline your ear, and come to me;
listen, so that you may live.
I will make with you an everlasting covenant,
my steadfast, sure love for David.
4 See, I made him a witness to the peoples,
a leader and commander for the peoples.
5 See, you shall call nations that you do not know,
and nations that do not know you shall run to you,
because of the Lord your God, the Holy One of Israel,
for he has glorified you.
New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org