John Calvin Commentary Isaiah 30:14

"And he shall break it as a potter`s vessel is broken, breaking it in pieces without sparing; so that there shall not be found among the pieces thereof a sherd wherewith to take fire from the hearth, or to dip up water out of the cistern." — Isaiah 30:14 (ASV)

And the breaking of it shall be. When a wall has fallen, some traces of the ruin are still to be seen, and its stones can be used, and to some extent, the wall can even be rebuilt.

But here the Prophet threatens that those who are puffed up with obstinacy against God shall perish in such a way that they cannot be restored, and all that is left of them shall be utterly useless. Accordingly, he employs the metaphor of a potter’s vessel, whose broken fragments cannot be repaired or put together.

These threats should make a deep impression on us, so that we embrace the word of God with reverence when we learn that punishments so severe are prepared for those who despise it; for the Prophet threatens that they shall be utterly destroyed and ruined, and takes away all hope of their being restored.

Nor is the threat groundless, for we see how those who despise God, when they have been cast down two or three times, still do not cease to raise their crests; for nothing is more difficult than to root out the false confidence from their hearts.