In Jeremiah 1:18, God makes Jeremiah a fortified city — both verses use metaphor for his appointed role as tester of people.

In Jeremiah 15:20, God makes Jeremiah a bronze wall — same metaphor of strength for his testing role.

In Ezekiel 3:8-10, God makes Ezekiel's forehead hard like flint — similar to making Jeremiah a metal tester, both for confrontation.

In Ezekiel 33:7, God makes Ezekiel a watchman to warn — similar to Jeremiah as metal tester to discern and warn.

In Ezekiel 20:4, God commands Ezekiel to judge Israel — both prophets are appointed to assess the people's ways.

In Ezekiel 22:2, God tells Ezekiel to judge the bloody city — similar to Jeremiah's role as tester of metals.