According to Reformed theology, why does God tell people to repent if they don't have the choice to do so, as in Exodus 10:3?

This question is addressed to those who believe in the doctrine of Total Depravity. In Exodus 10:3 God asks the Pharaoh for how long will he remain proud. Why does God ask such a question if the Pharaoh can't repent? And why does God tell all people to repent/or to not sin if they don't have the choice to do so? It's like telling a blind person to see. > "So Moses and Aaron went to Pharaoh and said to him, "This is what the LORD, the God of the Hebrews, says: 'How long will you refuse to humble yourself before me? Let my people go, so that they may worship me." ([Exodus 10:3](https://www.biblegateway.com/passage/?search=Exodus+10%3A3&version=NIV) (NIV))