Albert Barnes Commentary Jeremiah 18:23

"Yet, Jehovah, thou knowest all their counsel against me to slay me; forgive not their iniquity, neither blot out their sin from thy sight; but let them be overthrown before thee; deal thou with them in the time of thine anger." — Jeremiah 18:23 (ASV)

Yet, Lord — Better, But, Lord. They conceal their plots, but God knows, and therefore must punish.

Neither blot out ... — Or, “blot not out their sin from before Your face that they may be made to stumble before You.”

Thus — Omit this word. Since there is an acceptable time and a day of salvation, there is also a time of anger. Jeremiah’s prayer is that God would deal with his enemies at such a time, and when, as a result, no mercy would be shown. On imprecations such as these, see Psalms 109:0 (introductory note).

Though these imprecations did not flow from personal vengeance but from a pure zeal for God’s honor, they still belong to the legal spirit of the Jewish covenant. We must not, because we have been shown a more excellent way, condemn too harshly that sterner spirit of justice which animated so many saints of the earlier dispensation.