Commentaries
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.
10. to make a sore slaughter—literally, "that killing it may kill."
glitter—literally, "glitter as the lightning flash": flashing terror into the foe.
should we … make mirth—It is no time for levity when such a calamity is impending (Isa 22:12, 13).
it contemneth the rod of my son, &c.—The sword has no more respect to the trivial "rod" or scepter of Judah (Ge 49:10) than if it were any common "tree." "Tree" is the image retained from Eze 20:47; explained in Eze 21:2, 3. God calls Judah "My son" (compare Ex 4:22; Ho 11:1). Fairbairn arbitrarily translates, "Perchance the scepter of My son rejoiceth; it (the sword) despiseth every tree."