Genesis 42:7-23 NIV
As soon as Joseph saw his brothers, he recognized them, but he pretended to be a stranger and spoke harshly to them. “Where do you come from?” he asked.
“From the land of Canaan,” they replied, “to buy food.”
Although Joseph recognized his brothers, they did not recognize him. Then he remembered his dreams about them and said to them, “You are spies! You have come to see where our land is unprotected.”
“No, my lord,” they answered. “Your servants have come to buy food. We are all the sons of one man. Your servants are honest men, not spies.”
“No!” he said to them. “You have come to see where our land is unprotected.”
But they replied, “Your servants were twelve brothers, the sons of one man, who lives in the land of Canaan. The youngest is now with our father, and one is no more.”
Joseph said to them, “It is just as I told you: You are spies! And this is how you will be tested: As surely as Pharaoh lives, you will not leave this place unless your youngest brother comes here. Send one of your number to get your brother; the rest of you will be kept in prison, so that your words may be tested to see if you are telling the truth. If you are not, then as surely as Pharaoh lives, you are spies!” And he put them all in custody for three days.
On the third day, Joseph said to them, “Do this and you will live, for I fear God: If you are honest men, let one of your brothers stay here in prison, while the rest of you go and take grain back for your starving households. But you must bring your youngest brother to me, so that your words may be verified and that you may not die.” This they proceeded to do.
They said to one another, “Surely we are being punished because of our brother. We saw how distressed he was when he pleaded with us for his life, but we would not listen; that’s why this distress has come on us.”
Reuben replied, “Didn’t I tell you not to sin against the boy? But you wouldn’t listen! Now we must give an accounting for his blood.” They did not realize that Joseph could understand them, since he was using an interpreter.
NIV: New International Version