John Gill Commentary Jeremiah 44:29

"And this shall be the sign unto you, saith Jehovah, that I will punish you in this place, that ye may know that my words shall surely stand against you for evil:" — Jeremiah 44:29 (ASV)

And this [shall be] a sign unto you, says the Lord, that I will punish you in this place In Egypt, as before threatened; and what follows is a confirming sign that so it would be; and which, when observed by some, gave the hint to them to make their escape; though others, being hardened in their idolatry, impenitence, and unbelief, continued, and perished: that you may know that my words shall surely stand against you for evil ; which sign, when they should see, they might assure themselves that the threatenings of evil to them would certainly be accomplished, as sure as they saw the sign given, which is as follows: