Genesis 42:19

If ye [be] true [men]
As you say you are: let one of your brethren be bound in the house of your prison;
agree among yourselves which of you (for one of you must) remain in prison where you are: and the rest being set at liberty, go ye, carry corn for the famine of your houses;
Joseph, though he dealt with them after this manner to get what knowledge he could of his family, and to get sight of his brother, yet was concerned for the good of them and theirs, lest they should be in extreme want through the famine, and that they might have a speedy supply of corn, was not willing to detain them any longer.