Revenge is BIttersweet

The famine is so severe that Jacob sends his sons to buy grain in Egypt.  Joseph recognizes them, but they don't know him.  He speaks harshly to them and treats them rather roughly.  He accuses them of being spies and finally holds Simeon hostage until they go back to Canaan and return with their younger brother.  All of this sparks guilt in the brothers seeing these events coming upon them for what they had done previously to Joseph.