John Calvin Commentary Genesis 42:35

"And it came to pass as they emptied their sacks, that, behold, every man`s bundle of money was in his sack: and when they and their father saw their bundles of money, they were afraid." — Genesis 42:35 (ASV)

As they emptied their sacks. Here, again, it appears how greatly they had been alarmed on their journey, seeing that each had not at least examined his sack after money had been found in one. But these things are written to show that, as soon as people are smitten with fear, they have no particle of wisdom and no soundness of mind until God calms them.

Moreover, Joseph did not act with sufficient consideration, in that he caused very great grief to his father, whose poverty he really intended to relieve. From this we learn that even the most prudent are not always so careful, but that something may result from their actions that they do not wish.