Isaiah 55 is a call for all people—all the nations (v. 5)—to come to the Lord and experience the goodness of covenant relationship with Him. The picture is of God abundantly satisfying His people. Thirst-quenching water and the choicest of foods will be available at no cost.
Along with the invitation to the people to come and experience the Lord’s goodness is also an admonition for how they are to do this—through repentance (vv. 6-7). All who want to come to God must turn from their wicked ways and abandon their sinful thoughts and return to the Lord. Then He will have compassion on them and freely forgive.
The reason why repentance is essential is stated in verses 8-9: God’s ways and God’s thoughts are not ours. They are higher, loftier, and grander than anything we can muster. True repentance requires we grasp this, that we completely forsake any perceived goodness in our hearts and instead completely entrust ourselves to God’s mercy and grace. This is the one and only path to eternal joy and peace in Christ (vv. 12-13).
In what ways are you placing your trust in yourself rather than fully relying on God? Go to God in repentance for these ways and bathe in His mercy, grace, joy, and peace.