21:1-17 Here is an explanation of the parable in the last chapter. It is declared that the Lord was about to cut off Jerusalem and the whole land, that all might know it was his decree against a wicked and rebellious people. It behoves those who denounce the awful wrath of God against sinners, to show that they do not desire the woful day. The example of Christ teaches us to lament over those whose ruin we declare. Whatever instruments God uses in executing his judgments, he will strengthen them according to the service they are employed in. The sword glitters to the terror of those against whom it is drawn. It is a sword to others, a rod to the people of the Lord. God is in earnest in pronouncing this sentence, and the prophet must show himself in earnest in publishing it.
13. it is a trial—rather, "There is a trial" being made: the sword of the Lord will subject all to the ordeal. "What, then, if it contemn even the rod" (scepter of Judah)? Compare as to a similar scourge of unsparing trial, Job 9:23.
it shall be no more—the scepter, that is, the state, must necessarily then come to an end. Fulfilled in part at the overthrow of Judah by Nebuchadnezzar, but fully at the time of "Shiloh's" (Messiah's) coming (Ge 49:10), when Judea became a Roman province.