Joseph now has his brothers in his power. Consider the opportunity for revenge. Consider the opportunity to take everything they have ever done wrong and jam it right back down their throats.
Is that not a temptation for us sometimes as well? When we're right and we know we are right? It may have been years--after all, for Joseph it has been at least 2 years, and likely many more. Genesis 37:2 has Joseph at 17 years old and he enters Pharaoh's service at 30 (Genesis 41:46). Given that specific ages are usually mentioned to highlight when the events around them happen, that would suggest a gap of 20 years or more for Joseph, since the famine comes along seven years after he starts working for the Egyptian government.
Twenty years have passed, and now Joseph has all the power. It's like the dream of every kid who was an outcast of some kind in high school: at the reunion, nobody will pick on me anymore! They'll see I was right and they were wrong! Joseph could have slapped all of his brothers into prison, sent food back for his father with Benjamin and included a note that said "DAD! I'm alive!!"
Instead, in the midst of a time of trouble and famine, he orders a feast for his brothers. He brings them into his home, provides for their comfort--not just their needs--and pours out the wealth he has control over for their needs. They eat, they drink, and they drink to excess--it's not just a meal. It is a feast.
Then, there is one more test. Joseph has shown grace to his brothers, but he still wants to find out about their character. He has no way of knowing if Benjamin is safe with them or not, so he sets a trap to force the men to hand Benjamin over to him. For all the brothers know, Benjamin is going to be imprisoned, but Joseph may be seeking to protect his full-brother. If he can separate Benjamin, he can make sure that there are no pits for him in the years to come with his brothers.
His brothers, though, demonstrate their changed life. Judah offers himself in Benjamin's place, and Joseph sees that twenty years have changed his brothers as they have changed him.
What do we learn?
First, without a doubt, we see the extravagance of grace. Grace forgives and restores, grace throws a feast in the midst of a famine, and does not hold back even in the face of cultural opposition. (See that Joseph dines by himself, because he's the boss, but by Genesis 43:34, the brothers are 'with' Joseph. Intoxicated, but with nonetheless.)
Do we show that type of grace? Are we willing to embrace that God is that forgiving toward us and that we can, and should, be that forgiving toward others?
Second, though, we should also see our responsibility for the welfare of others. When we have seen a pattern of destruction by some, we must extend grace while still defending the next potential victim. This is the important partner lesson here: Joseph was, it appears, working to help protect his youngest brother from his other brothers.
Do we do that? Do we understand that it is not graceful to leave someone in the midst of abuse or danger? We have to understand this. Grace is bought by the blood of Christ, and so should not be paid for again by the blood of victims.
Third, we need to acknowledge that people change over the course of time. I look back at my own life and see this. I've been working for churches for more than 2 decades at this point. In many ways, I don't know that 18 year-old youth minister Doug would recognize 41 year-old Pastor Doug. I'm not even sure the 2 would get along that well. Time changes us, hopefully for the better. Or at least makes a bit more mature.
Be careful evaluating someone because of who they were. Even as adults, we change, we grow, we learn from our mistakes. That does not exempt us from certain consequences, especially if we evaded them in our younger years, but it does show how some folks can persuade you now that they are wonderful when they were troublesome in the past.
Show grace, watch out for others, and allow for time to work in your life and other people's lives. In essence, realize that people are best known through relationships and not spreadsheets.