Reading through the Bible is a dangerous exercise. I remember doing it for the first time as a teenager and being quite struck and disoriented when I came to Exodus 4:21:
And the LORD said to Moses, “When you go back to Egypt, see that you do before Pharaoh all the miracles that I have put in your power. But I will harden his heart, so that he will not let the people go. (Exodus 4:21 ESV)
What does it mean that God hardened Pharaoh’s heart?