What does Genesis 42:17 mean?

The recent turn of events probably bewildered Joseph's brothers. After coming to buy food (Genesis 42:1–5), they have been accused by the governor of being spies (Genesis 42:6–14). What they don't realize is that the governor is their long-lost brother, Joseph, whom these ten men sold into slavery twenty years earlier (Genesis 37:28). His interrogating, accusing questions would have been frightening and unexpected.

Even the resolution proposed by the Egyptian governor seems strange. Why would he think that bringing their youngest brother to him would prove they are not spies (Genesis 42:15–16)? Modern readers might be confused by Joseph's actions, as well. He knows who they are. He remembers all they have done to him. We might wonder if he is deciding whether to take revenge on them. The only thing which seems clear here is that Joseph desperately wants to see his younger brother Benjamin; this was the only brother who had no part in selling him into slavery.

Later verses show that Joseph's intentions, though coupled with righteous anger (Genesis 42:7), are good (Genesis 42:23–24; 43:30; 45:1–5). His end goal is rescuing the family from starvation (Genesis 47:11–12). Everything he does here is a form of testing and preparation for those results.

Prior to letting one brother leave, while the rest remain in custody, Joseph locks them all up together for three days. Apparently, he needs time to decide exactly how to proceed.