Charles Ellicott Commentary Jeremiah 43:9

"Take great stones in thy hand, and hide them in mortar in the brickwork, which is at the entry of Pharaoh`s house in Tahpanhes, in the sight of the men of Judah;" — Jeremiah 43:9 (ASV)

Take great stones in your hand, and hide them in the clay in the brickkiln. —Better, in the mortar on the platform. There seems something incongruous in the idea of a brickkiln, or a place for baking bricks, at the entrance of a royal palace; nor is it easy to see why Nebuchadrezzar should have chosen it as a place for his throne. It seems better, with Hitzig, Furst, and others, to take the Hebrew word, which occurs only here and in 2 Samuel 12:31 and Nahum 3:14, as meaning a structure of brick, a dais or raised pavement, like the Gabbatha or Pavement on which Pilate sat (John 19:13), in front of the entrance of the palace, on which the king naturally placed his throne when he sat in judgment or received petitions. Assyrian and Babylonian monuments present many instances of kings thus seated.

To make his prediction more vivid, the prophet places stones in the mortar or cement (not “clay”) with which the mass was covered, and conceals them apparently with a fresh coat of mortar. There they were to remain until his prediction should be fulfilled. The symbolic act was of the same type as the breaking of the potter’s vessel in Jeremiah 19:10, the yoke worn on the prophet’s shoulders (Jeremiah 27:2), and Ezekiel’s digging through the wall (Ezekiel 12:7). It may be noted that our version follows Luther in translating “brickkiln.” The Septuagint evades the difficulty by taking refuge in vague terms: “in the vestibule (πρόθυρα), in the gate of the house,” and the Vulgate gives “in the crypt which is under the brick walls.”