Plummet
The plumb-line and plummet appear in the prophets as builders' tools turned into instruments of divine measurement. Three texts use the figure: Amos sees Yahweh standing by a wall with a plumb-line; Zechariah sees the plummet in the hand of Zerubbabel as the temple is rebuilt; Isaiah hears Yahweh make justice the line and righteousness the plummet against a refuge of lies.
Yahweh Beside the Wall
Amos's third vision is of Yahweh measuring his people by the same standard a builder uses to test a wall:
"Thus he showed me: and, look, the Lord stood beside a wall made by a plumb-line, with a plumb-line in his hand." (Am 7:7).
The dialogue that follows turns the tool into a verdict — Israel will be measured and not passed by again:
"And Yahweh said to me, Amos, what do you see? And I said, A plumb-line. Then said the Lord, Look, I will set a plumb-line in the midst of my people Israel; I will not again pass by them anymore;" (Am 7:8).
The Plummet in Zerubbabel's Hand
In Zechariah's vision-cycle, the plummet is identified with the day of small things and with the rebuilding work of the post-exilic governor:
"For who has despised the day of small things? For these seven will rejoice, and will see the plummet in the hand of Zerubbabel; [these are] the eyes of Yahweh, which run to and fro through the whole earth." (Zec 4:10).
The plummet is paired here with the seven all-seeing eyes — the tool of construction and the instrument of inspection held together.
Justice the Line, Righteousness the Plummet
Isaiah's oracle against the scoffers in Jerusalem makes the figure verbal: the standards of judgment themselves are named as builders' tools, and what cannot stand by them is swept away:
"And I will make justice the line, and righteousness the plummet; and the hail will sweep away the refuge of lies, and the waters will overflow the hiding-place." (Isa 28:17).
The instrument that tests true vertical becomes the figure for the standard against which Yahweh assesses, and dismantles, what is built crooked.