Matthew Henry Commentary Jeremiah 40:1-6

"The word which came to Jeremiah from Jehovah, after that Nebuzaradan the captain of the guard had let him go from Ramah, when he had taken him being bound in chains among all the captives of Jerusalem and Judah, that were carried away captive unto Babylon. And the captain of the guard took Jeremiah, and said unto him, Jehovah thy God pronounced this evil upon this place; and Jehovah hath brought it, and done according as he spake: because ye have sinned against Jehovah, and have not obeyed his voice, therefore this thing is come upon you. And now, behold, I loose thee this day from the chains which are upon thy hand. If it seem good unto thee to come with me into Babylon, come, and I will look well unto thee; but if it seem ill unto thee to come with me into Babylon, forbear: behold, all the land is before thee; whither it seemeth good and right unto thee to go, thither go. 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. Then went Jeremiah unto Gedaliah the son of Ahikam to Mizpah, and dwelt with him among the people that were left in the land." — Jeremiah 40:1-6 (ASV)

The captain of the guard seems to exult that he had been God's instrument to fulfill what Jeremiah had been God's messenger to foretell. Many can see God's justice and truth concerning others, while they themselves are unmindful and blind regarding their own sins. But, sooner or later, all people will be made aware that their sin is the cause of all their miseries.

Jeremiah is given permission to decide his own course; but is advised to go to Gedaliah, governor of the land under the king of Babylon. It is doubtful whether Jeremiah acted rightly in this decision. But those who desire the salvation of sinners and the good of the church are inclined to expect better times from slight indications, and they will prefer the hope of being useful to the most secure situations, even if those situations offer no such opportunity for usefulness.