Genesis 42:21

We are verily guilty. — They had evidently expected that whatever suspicions might be aroused by their first appearance, all such ideas would disappear upon their explanation of themselves and their purpose. Instead of this they are thrown into prison, abandoned to their reflections for three days, and dismissed only upon the condition of their leaving one brother as a hostage for their coming again accompanied by Benjamin: and as they knew no reason for this, it would fill their minds with fear. But though they were now suffering unjustly, it brought back to their mind their former sin; and the fact that it was so fresh in their memories is a sign of the reality of their repentance.