Charles Ellicott Commentary Jeremiah 50:21

"Go up against the land of Merathaim, even against it, and against the inhabitants of Pekod: slay and utterly destroy after them, saith Jehovah, and do according to all that I have commanded thee." — Jeremiah 50:21 (ASV)

Go up against the land of Merathaim. No such name is found in Babylonian inscriptions or is mentioned by historians. The most probable explanation of its use is that the prophet coined it as a descriptive word (meaning "land of two rebellions"), and then substituted it, in his usual way (as with Sheshach, Jeremiah 25:6; Magor-missabib, Jeremiah 20:3), for the name Aram-Naharaim (meaning "land of the two rivers," or Mesopotamia), which was, as in Genesis 24:10, Deuteronomy 23:4, Judges 3:8, and Judges 3:10, the recognized name of the country between the Tigris and Euphrates.

It was, he seems to say, the country not of rivers, but of rebellions. He chose the dual form partly for the sake of assonance, and partly to express the fact that Babylon, having rebelled against Assyria (as, for example, Merodach-baladan in Isaiah 39:1 and Nabopolassar had done), had also rebelled against Jehovah. Possibly, however, the dual form may simply express intensity. Such changes of names were quite characteristic of Old Testament usage. For instance, Beth-aven was substituted for Bethel (Hosea 10:5), and Mephibosheth for Meribbaal (2 Samuel 4:4; 1 Chronicles 8:34).Micah 1:0 is full of such paronomasiae.

Against the inhabitants of Pekod. Here we have a name found in Ezekiel 23:23 and in inscriptions as that of a Babylonian town (as in a list of rebels, and in the form Bukudu, as in the Cylinder of Sennacherib, Records of the Past, vol. 1, p. 26). It is also the name of a city, Nahar-Pekod, mentioned in the Talmud (Fürst, Lexicon, s.v., and Neubauer, Géographie du Talmud, p. 363).

We can hardly doubt, however, that the prophet chose this name for the sake of its meaning, “visitation.” It was necessary to find a word that would be at once a nomen et omen for the guilt of Babylon. A word applicable to its punishment was readily available.

Waste and utterly destroy. A better translation is, slay and devote to destruction. The latter verb is connected with the Hebrew word Cherem, which expressed, as in Deuteronomy 7:26 and Joshua 7:13, the idea of a solemn anathema.