“I will smash this nation and this city just as this potter's jar is smashed and cannot be repaired.” (Jeremiah 19:11)
The LORD tells Jeremiah: go and buy a clay jar from a potter. Take along some of the elders of the people and of the priests and go out to the Valley of Ben Hinnom, near the entrance of the Potsherd Gate. There proclaim the words I tell you. Say: hear the word of the LORD, you kings of Judah and people of Jerusalem. This is what the LORD Almighty, the God of Israel, says: I am going to bring a disaster on this place that will make the ears of everyone who hears of it tingle. Then smash the jar before those who have come with you and say: this is what the LORD Almighty says: I will smash this nation and this city just as this potter's jar is smashed and cannot be repaired.
The Catechism draws from Jeremiah's sign actions the principle that prophetic communication uses the whole body and physical objects to convey the divine word: the smashed jar speaks what words alone cannot (CCC 702).
Brothers and sisters, in chapter 18 the marred clay is reshaped; in chapter 19 the hardened jar is smashed beyond repair. The difference is the moment: soft clay can be reshaped; the fired jar cannot. The time for reshaping is now, while the clay is still soft. Do not let your heart harden past the point of reformation.
Lord God, keep our hearts soft clay in your hands, never the hardened jar that is beyond repair. Through Christ our Lord. Amen.