By the type of breaking an earthen vessel, Jeremiah is to predict the destruction of Judah.
Jer.19:1-9 The prophet must give notice of ruin coming upon Judah and Jerusalem. Both rulers and ruled must attend to it. That place which holiness made the joy of the whole earth, sin made the reproach and shame of the whole earth. There is no fleeing from God's justice, but by fleeing to his mercy.
Jer.19:10-15 The potter's vessel, after it is hardened, can never be pieced again when it is broken. And as the bottle was broken, so shall Judah and Jerusalem be broken by the Chaldeans. No human hand can repair it; but if they return to the Lord he will heal. As they filled Tophet with the slain sacrificed to their idols, so will God fill the whole city with the slain that shall fall as sacrifices to his justice. Whatever men may think, God will appear as terrible against sin and sinners as the Scriptures state; nor shall the unbelief of men make his promise or his threatenings of no effect. The obstinacy of sinners in sinful ways, is their own fault; if they are deaf to the word of God, it is because they have stopped their ears. We have need to pray that God, by his grace, would deliver us from hardness of heart, and contempt of his word and commandments.