John Gill Commentary Jeremiah 41:13

"Now it came to pass that, when all the people that were with Ishmael saw Johanan the son of Kareah, and all the captains of the forces that were with him, then they were glad." — Jeremiah 41:13 (ASV)

Now it came to pass, [that], when all the people who [were] with Ishmael That is, those whom he had brought captives from Mizpah; not those that came with him there: saw Johanan the son of Kareah, and all the captains of the forces that [were] with him, they were glad; seeing them as their deliverers; hoping through them to be preserved from being carried captives to the king of Ammon.