What does Jeremiah 34:13 mean?

All the princes and all the people obeyed who had entered into the covenant, that everyone should let his male servant, and everyone his female servant go free, that no one should make bondservants of them any more. They obeyed and let them go;

but afterwards they turned, and caused the servants and the handmaids, whom they had let go free, to return, and brought them into subjection for servants and for handmaids.

Therefore Yahweh’s word came to Jeremiah from Yahweh, saying,

At the end of seven years, every man of you shall release his brother who is a Hebrew, who has been sold to you, and has served you six years. You shall let him go free from you; but your fathers didn’t listen to me, and didn’t incline their ear.

You had now turned, and had done that which is right in my eyes, in every man proclaiming liberty to his neighbor. You had made a covenant before me in the house which is called by my name;

but you turned and profaned my name, and every man caused his servant, and every man his handmaid, whom you had let go free at their pleasure, to return. You brought them into subjection, to be to you for servants and for handmaids.’”