John Trapp on Jeremiah 20:12

Ver. 12. But O Lord of hosts] See chap. 11.20. and 17.10.

Let me ſee thy vengeance on them] Some pert and pride themſelves over the Miniſtery, as if it were a dead Alexanders noſe, which they might wring off, and not fear to be called to account therefore: but the viſible vengeance of God, will ſeiſe ſuch one day, as it did Pharaoh, Ahab, Herod, Julian.

For unto thee have I opened my cauſe] Prayer is an opening of the ſouls cauſes and caſes to the Lord. The ſame word for opened here, is in another conjugation uſed for uncovering, making bare, and naked, Gen 9.21. Gods people in prayer do or ſhould nakedly preſent their ſouls cauſes without all cover-ſhames, or ſo much as a ragge of ſelf or fleſh cleaving to them.