John Gill Commentary Jeremiah 16:3

"For thus saith Jehovah concerning the sons and concerning the daughters that are born in this place, and concerning their mothers that bare them, and concerning their fathers that begat them in this land:" — Jeremiah 16:3 (ASV)

For thus says the Lord concerning the sons and concerning the daughters that are born in this place and concerning their mothers that bore them, and concerning their fathers that begot them in this land. This is a reason given why the prophet should not have, and why he should not be desirous to have, sons and daughters in such a place and country, devoted to destruction:

the land of Judea; which shows what is meant by the place before mentioned; both the one and the other, parents and children, should die there; this is what was determined by the Lord concerning them; and therefore it could not be a desirable thing for a man to have wife and children, whom he must part with in such an uncomfortable manner, as is after described; and to show the certainty of which the prophet is forbid to do as above.