Sermon Illustrations for Proper 10 | OT 15 (2013)
A builder uses a plumb line to determine true vertical from the gravitational center of the earth, not the particular topography of the land. Only in this way can bricks be laid to create a vertical wall that will not topple from being "off center." It is of simple construction: a string with a weight attached at the bottom. Amos uses the metaphor of the plumb line to announce to Israel that God is measuring how true or "off center" Israel is to God's purposes.
Mark M.
Amos 7:7-17