Isaiah spoke of our natural desire and need for food when conveying God's desire for his people to seek the Kingdom. Come, everyone who thirsts, come to the waters; and he who has no money, come, buy and eat! Come, buy wine and milk without money and without price (Isaiah 55:1). Notice both the urgency and the universal tone of the invitation. Come. Right now. No cost prohibition here. All that is required is a hunger and thirst for the things of our Lord.
Verse 2 continues: Why do you spend your money for that which is not bread, and your labor for that which does not satisfy? Listen diligently to me, and eat what is good, and delight yourselves in rich food. Isaiah exposes the foolishness of wasting time and effort on things that don't satisfy; such as pursuing worldly pleasures or recognition. We instead are invited to an all-you-can-eat banquet of goodness that only requires us to diligently listen and respond to the Gospel of Christ.
Just as food is essential for our nourishment and survival, the invitation to God's banquet ensures that our souls will live in an everlasting covenant with the Creator of all (v. 3). Time to dig in!