John Gill's Exposition of the Whole Bible
Jeremiah 42:18
For thus saith the Lord of hosts, the God of Israel,....
as mine anger and my fury hath been poured forth upon the inhabitants of Jerusalem; like a large hasty shower of rain; or rather like melted metal, which suddenly and swiftly runs, and spreads itself, and burns and consumes with a violent heat; such was the wrath of God on Jerusalem, in the destruction of it by the Chaldeans:
so shall my fury be poured forth upon you, when ye shall enter into Egypt; as soon as they had well got there, quickly after they were settled there; for it was in the time of the then present king of Egypt, Pharaohhophra, and by the then present king of Babylon, Nebuchadnezzar, that the destruction of Egypt was, in which these Jews suffered:
and ye shall be an execration, and an astonishment, and a curse, and a reproach; men should be astonished at the hand of God upon them, reproach them for their sins; and when they made any imprecation on themselves, it would be in this form, if it be so, let the same calamities come upon me as upon the Jews in Egypt:
and ye shall see this place no more; and so their case would be worse than their brethren in Babylon; who, after a term of years were expired, would return to their own land, which these would never see any more.