What does Genesis 42:28 mean?Joseph's ten older brothers are reacting to a terrible discovery. They went to Egypt to buy grain (Genesis 42:1–5). They were then strangely accused of being spies by the governor (Genesis 42:12). He only released them on condition they bring back their youngest brother, Benjamin (Genesis 42:18–20). The men don't realize this governor is their lost brother, Joseph, whom they had sold as a slave some twenty years before (Genesis 37:28).
In another secret action, Joseph had the money the brothers paid for grain returned to their packs (Genesis 42:25–27). This might have been an act of kindness—except he did not tell them about it. It might have been another way to create accusations later. We don't know the exact reasons, though these passages make it clear revenge is not Joseph's ultimate motive (Genesis 47:11–12).
As one would expect, Joseph's brothers take this discovery very badly. Understandably, their first response is confusion and panic. They know they did not do this on purpose, but also know how bad this would look. Most people would immediately conclude they'd stolen from the Egyptian governor. They could be put to death for this, or their brother Simeon, still in captivity (Genesis 42:24), could suffer consequences.
As they did earlier, they also express a measure of guilt (Genesis 42:21–22). Saying, "what has God done to us?" implies they interpreted this event as further punishment. Their pain is enhanced by knowing that they are, once again, returning to their father short one brother (Genesis 37:31–33), and need to ask to take their youngest back with them into Egypt.