Genesis 42:9-12, 14-17, 19-20

And he remembered the dreams he’d had about them many years before. He said to them, “You are spies! You have come to see how vulnerable our land has become.” “No, my lord!” they exclaimed. “Your servants have simply come to buy food. We are all brothers—members of the same family. We are honest men, sir! We are not spies!” “Yes, you are!” Joseph insisted. “You have come to see how vulnerable our land has become.”

But Joseph insisted, “As I said, you are spies! This is how I will test your story. I swear by the life of Pharaoh that you will never leave Egypt unless your youngest brother comes here! One of you must go and get your brother. I’ll keep the rest of you here in prison. Then we’ll find out whether or not your story is true. By the life of Pharaoh, if it turns out that you don’t have a younger brother, then I’ll know you are spies.” So Joseph put them all in prison for three days.

If you really are honest men, choose one of your brothers to remain in prison. The rest of you may go home with grain for your starving families. But you must bring your youngest brother back to me. This will prove that you are telling the truth, and you will not die.” To this they agreed.