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

And Joseph remembered his dreams about his brothers bowing to him. He said to them, “You are spies! You came to learn where the nation is weak!” But his brothers said to him, “No, my master. We come as your servants just to buy food. We are all sons of the same father. We are honest men, not spies.” Then Joseph said to them, “No! You have come to learn where this nation is weak!”

But Joseph said to them, “I can see I was right! You are spies! But I will give you a way to prove you are telling the truth. As surely as the king lives, you will not leave this place until your youngest brother comes here. One of you must go and get your brother. The rest of you will stay here in prison. We will see if you are telling the truth. If not, as surely as the king lives, you are spies.” Then Joseph put them all in prison for three days.

If you are honest men, let one of your brothers stay here in prison while the rest of you go and carry grain back to feed your hungry families. Then bring your youngest brother back here to me. If you do this, I will know you are telling the truth, and you will not die.” The brothers agreed to this.