I have set thee, etc.; literally, as an assayer have I set thee among my people, a fortress. Various attempts have been made to avoid giving the last word its natural rendering, "a fortress." Ewald, for instance, would alter the points, and render "a separator [of metals]," thus making the word synonymous with that translated "an assayer;" but this is against Hebrew usage.
Hitzig, assuming a doubtful interpretation of Job 22:24, renders " … among my people without gold," i.e. "without there being any gold there for thee to essay" (a very awkward form of expression). These are the two most plausible views, and yet neither of them is satisfactory.
Nothing remains but the very simple conjecture, supported by not a few similar phenomena, that mibhcar, a fortress, has been inserted by mistake from the margin, where an early glossator had written the word, to remind of the parallel passage (Jeremiah 1:18, "I have made thee this day a fortress-city," 'it mibhcar).
In this and the following verses metallurgic phraseology is employed with a moral application (comp. Isaiah 1:22, Isaiah 1:25).