I have set (u) thee [for] a tower [and] a fortress among my people, that thou mayest know and try their way.
(u) Meaning, Jeremiah, whom God had appointed to try out the godly from the wicked, as a founder does the pure metal from the dross.
Related Commentaries of Jeremiah 6:27
Jeremiah 6:27
27 I have set thee for a tower and a fortress among my people, that thou mayest know and try their way.