John Calvin on Jeremiah 41:14

The people readily passed over to John and his army, because John, and other leaders of the forces, came to them sufficiently armed, and they were, as we have before seen, men trained up for war. And Ishmael could not have been equal to them, when the people went over to John and his associates. Thus we see that the impious man failed in his base purpose, for he thought to render himself very acceptable to the king of Ammon by bringing so many captives to dwell in his land, that he might take possession of Judea. He had then formed many plans for himself, but God frustrated them. But it was God’s will that he should remain alive; for he fled, as it appears from what follows, —

Jeremiah 41:15

15. But Ishmael the son of Nethaniah escaped from Johanan with eight men, and went to the Ammonites.

15. Et Ismael (Ismael autem) filius Nathaniae servatus est (vel, evasit) cum octo hominibus a facie Joannis, et pro-fectus eat ad filios Ammon.