What does Genesis 42:10 mean?

Few people would blame Joseph for being harsh, or even vengeful, upon seeing his brothers once again (Genesis 37:28; 42:6–9). He certainly seems angry (Genesis 42:7). And yet, his accusations and tough speech are also meant to disguise his own emotions (Genesis 42:23–24). Throughout what happens in the next few chapters, his actions are meant to test and prepare his brothers, whom he seeks to rescue (Genesis 43:30; 45:1–5). The end of Joseph's plan is to bring the entire family into safety in Egypt (Genesis 47:11–12).

Joseph's brothers recoil at the idea that they are spies. They recognize how serious the charge is. It could lead to their imprisonment or execution. They restate their true purpose for being in Egypt. They have come to buy food (Genesis 42:1–5) like everyone else afflicted by the famine (Genesis 41:55–56).