Confinement (v. 17). Joseph put his brothers in confinement for three days, just to teach them what it was like to be prisoners and to give them time to think. The kjv translates the Hebrew word as “prison” (or “ward”) in verse 17, but “in custody” would be closer to the original. The word translated “prison” in Genesis 39–40, describing Joseph’s experiences, means a prison and not just being under guard or house arrest. Joseph suffered as a prisoner in a real prison, while his brothers were only confined under guard. But it taught them a lesson. When they were released three days later, the ten men were beginning to sense that God was dealing with them because of their sins (42:21).

Surety (vv. 15-16, 18-20). Since the ten brothers insisted that they were honest men, Joseph gave them an opportunity to prove it. He ordered them to send one of their number to Canaan to bring Benjamin to Egypt. He would keep the other nine brothers in confinement until Benjamin arrived in Egypt to prove that their story was true.

But then Joseph changed the test. He would keep only one brother as security while all the others returned home to get Benjamin and bring him to Egypt. Joseph wisely concluded that the men would eventually have to return to Egypt for more grain and would be forced to bring Benjamin with them or else go hungry. Furthermore, it was much safer for a group of men to travel than for only two men to make the journey, and the men did have many sacks of grain to carry.

Joseph was genuinely concerned about his family in Canaan and didn’t want them to starve. At the same time, he wanted to see God’s promises fulfilled so he could be reconciled with his brothers and his father. He had God’s assurance that all eleven brothers would eventually bow before him, but he wanted to motivate his brothers to act. That’s why he kept Simeon as hostage.