Albert Barnes Commentary Jeremiah 23:5

"Behold, the days come, saith Jehovah, that I will raise unto David a righteous Branch, and he shall reign as king and deal wisely, and shall execute justice and righteousness in the land." — Jeremiah 23:5 (ASV)

Even with the temporal kingship abolished, David’s mercies are still sure.

A righteous Branch - Or, sprout, germ (see Isaiah 4:2 note). The sprout is that in which the root springs up and grows, and which, if it is destroyed, makes the root perish also.

And a king shall reign ... - Rather, and he shall reign as king. David’s family is to be dethroned (temporally), that it may reign gloriously (spiritually). But compare Jeremiah 33:17, note; Jeremiah 33:25, note.