(5) It shall not return any more--i.e., until it has fully accomplished its purpose. Other judgments upon Israel had been arrested in mercy--the sword had been returned to the scabbard while its work was still incomplete. This will go on to the end.

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.That all flesh may know that I the Lord have drawn forth my sword out of his sheath,.... The same with kindling a fire in Judea; see Gill on Ezekiel 20:48,

it shall not return any more; that is, into its sheath, until it has done all its work; meaning that the Chaldean army should not return to their own land until they had executed the whole will of God upon the Jews; this is the fire that should not be quenched, Ezekiel 20:48 and here ends the explanation of the said prophecy.