In Revelation 11, John is given a rod to measure out the courts of the temple. That picks up on the imagery of Ezekiel 40ff, where a bronze man measures out the holy space of the new temple.
But there are other rods in the Old Testament. Egypt is a rod (Ezkiel 29:6), an unreliable rod that will only pierce the hand of Israel if they choose to lean on it. And behind that is the rod of Moses, used for “measuring” judgment to the Egyptians. That imagery is linked too to the imagery of the plumb line that tests whether Israel is “square” or not.
Rods have at least a double connotation – measuring holy space and carrying out judgments – and these two associations overlap, since it is the Holy One who does righteousness.