Charles Ellicott Commentary Genesis 42:21

"And they said one to another, We are verily guilty concerning our brother, in that we saw the distress of his soul, when he besought us, and we would not hear; therefore is this distress come upon us." — Genesis 42:21 (ASV)

We are truly 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 on the condition that they leave one brother as a hostage for their coming again accompanied by Benjamin. 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.