Forgiveness is allowing God to be the judge, jury and executioner for the offense committed. Forgiveness means letting go of the need to punish someone for what they have done to you because you recognize that it's God's job to make things right, not your own. Forgiveness does NOT mean that you allow the person to continue to harm you, mentally, physically or emotionally. It does not mean that the relationship is healed or restored--that requires reconciliation. Reconciliation is a process in which the offender has the responsibility to make things right. This includes includes repentence, restitution, and lots of reassurance that it won't happen again, sometimes in the form of boundaries that prevent the offense from happening again.
In light of his brother's behavior twenty years earlier, Joseph had the right to some real concerns about how his brothers would treat him and Benjamin, particularly since the tables had turned. It's easy to say you're sorry when the one you've offended has all the power--you really don't have a choice--but that's not true repentence. Joseph needed to see that his brothers had changed, particularly the ringleaders, Judah and Simeon. If they were still murderously jealous and impulsively vicious (remember Dinah?) after all that time with no consideration for who they hurt along the way, he would still provide for them but the relationship could not be a close one. It wouldn't be wise or safe. Their responses have to show Joseph if he can extend an olive branch or an iron fist, so Joseph has to put them in positions that will test their character. The key is with Benjamin. When Joseph left, Benjamin probably wasn't very old. If given the chance, would they sell out their brother again? Did they regret any of what happened before?
First, Joseph accuses them of treachery and throws them all in prison for 3 days. It's a ruse, but it was important for them to understand the nature of what they done to Joseph and it will reinforce that they need to come back soon to rescue their brother from jail. When he keeps Simeon and sends the rest home, the brothers have the confirmation that karma is out to get them--everyone remembers who did the selling. Joseph gets his first painful clue into their hearts as they regretfully link their crime to their current circumstances.
They eventually return with Benjamin, to Joseph's great delight. He lavishes Benjamin with special treatment, watching closely to see if any of the old jealousy remains. The cup in Benjamin's bag is the last test. Everyone is free to go, but Benjamin must stay for his "crime". When Judah offers his own life to save his father grief, Joseph can finally be confident that the men who stand before him are not the same as the ones who sent him away twenty years ago. The reunion is a private one. Joseph has no idea how his brothers will ultimately react to his revelation. Joseph is still the leader of Egypt and addressing his personal matters privately shows great discretion. The happy outcome of the revelation makes it back to Pharoah and he is just as overjoyed at it as Joseph is.
This family will live happily ever after, though their 4th generation will have some issues in the future. We will see in a few chapters that the brothers remain skeptical about Joseph's forgiveness but have no need for their fears. Things really do turn out for the best and Joseph understands the big picture in a way that few can.
Who do you need to forgive? Does it make it easier to forgive them knowing that you have a right (even a responsibility) to protect yourself from the offense happening again? Does it make it easier knowing that God is the ultimate judge and can handle their punishment or grace much better than you can?