Genesis 42:15-20

ISV(i) 15 So here’s how we’ll test you. You can bet the life of Pharaoh that you’re not leaving here until your youngest brother comes here! 16 One of you is to be sent back so he can get your brother while the rest of you remain in custody. That way, we’ll test whether or not you’re telling the truth. If you’re not, as surely as the Pharaoh lives, you’re spies!”
17 Then Joseph locked them all together in prison for three days. 18 Three days later, Joseph told them, “I fear God, so do this and you’ll live. 19 If you’re honest men, leave one of your brothers here in custody, then the rest of you can leave and take some grain with you to alleviate the famine that’s affecting your households. 20 Just be sure to bring your youngest brother back to me so what you’ve claimed can be verified. That way, you won’t die.”