Charles Ellicott Commentary Jeremiah 18:21

"Therefore deliver up their children to the famine, and give them over to the power of the sword; and let their wives become childless, and widows; and let their men be slain of death, [and] their young men smitten of the sword in battle." — Jeremiah 18:21 (ASV)

Therefore deliver up their children ... —The bitter words that follow startle and pain us, like the imprecations of Psalms 35, Psalms 69, and Psalms 109. To what extent they were the utterances of a righteous indignation, a true zeal for God, which had not yet learned the higher lesson of patience and forgiveness, or embodied an element of personal vindictiveness, we are not called on to inquire, and could not, in any case, decide.

It is not ours to judge another man’s servant. In all like cases we have to remember that the very truthfulness with which the prayer is recorded is at least a proof that the prophet felt, like Jonah, that he did well to be angry (Jonah 4:9), that a righteous anger is at least one step towards a righteous love, and that we, as disciples of Christ, have passed, or ought to have passed, beyond that earlier stage.

Pour out their blood by the force of the sword. —Literally, with a bolder metaphor, pour them out into the hands of the sword.