Albert Barnes Commentary Jeremiah 40:5

"Now while he was not yet gone back, Go back then, [said he], to Gedaliah the son of Ahikam, the son of Shaphan, whom the king of Babylon hath made governor over the cities of Judah, and dwell with him among the people; or go wheresoever it seemeth right unto thee to go. So the captain of the guard gave him victuals and a present, and let him go." — Jeremiah 40:5 (ASV)

Now while he had not yet gone back - Most modern commentators render, “And as he still answered nothing, Return then, he said, to Gedaliah...”

Victuals - A ration of food.

A reward - A present.