Amos 7:7-9

Thus He showed me [a vision], and behold, the Lord was standing by a vertical wall with a plumb line in His hand [to determine if the wall was straight or if it needed to be destroyed]. [2 Kin 21:13; Is 34:11] The LORD said to me, “Amos, what do you see?” And I said, “A plumb line.” Then the Lord said, “Behold, I am setting a plumb line [as a standard] Among My people Israel [showing the defectiveness of the nation, requiring judgment]. I shall not spare them any longer. [The door of mercy is shut.] “And the [idolatrous] high places of Isaac (Israel) will be devastated and deserted, And the sanctuaries of Israel will be in ruins. Then I shall rise up against the house of Jeroboam with the sword [and destroy the monarchy].”