The clay on the wheel was not suitable for the intended design of the potter. He must make a different vessel than the original design called for.

Jehovah is the potter. Apostate Judah is the clay. A people who break his covenant and reject his sovereignty are not material through which God will fulfill his original purpose for a faithful people. Now, due to their apostasy, they must be made to serve the purposes of judgment.

This section highlights the absolute sovereignty of God over Judah. He tells her "so are you in my hand!" (18:6). And the spiritual condition of the nation determines what the Potter will make out of his clay.