Charles Ellicott Commentary Jeremiah 21:6

"And I will smite the inhabitants of this city, both man and beast: they shall die of a great pestilence." — Jeremiah 21:6 (ASV)

They shall die of a great pestilence. —This was undoubtedly, as in other instances (Thucydides 2.52), the natural consequence of the siege, but it came before the people as another proof that Jehovah had stretched out his arm against them, that they were fighting against that arm as well as against the host of the invaders. The “outstretched hand” may be noted as another Deuteronomic phrase (Deuteronomy 4:34; Deuteronomy 5:15; Deuteronomy 26:8).