Albert Barnes Commentary Jeremiah 33:14

"Behold, the days come, saith Jehovah, that I will perform that good word which I have spoken concerning the house of Israel and concerning the house of Judah." — Jeremiah 33:14 (ASV)

That good thing – Better, the good word (Jeremiah 29:10), with reference to the promise already given (Jeremiah 23:5–6).