John Wesley on Isaiah 28:17

Plummet - I will execute just judgment, as it were by a line and plummet annexed to it; that is, with exactness and care: I will severely punish, and utterly destroy all who reject that stone. For the line and plummet, or the plumb - line, was not only used in erecting buildings, but also in pulling them down; those parts of the building being thus marked out, which were to be demolished.