"I have set you as an assayer and a fortress among My people, That you may know and test their way.
Jeremiah 6:27
Surrounding context
6:26 O daughter of my people, Dress in sackcloth And roll about in ashes! Make mourning as for an only son, most bitter lamentation; For the plunderer will suddenly come upon us.
6:27 "I have set you as an assayer and a fortress among My people, That you may know and test their way.
6:28 They are all stubborn rebels, walking as slanderers. They are bronze and iron, They are all corrupters;