Exodus 6:9

6:9 Moses told this to the Israelites, but they did not listen to him because of their discouragement and hard labor.

Exodus 7:13-14

7:13 Yet Pharaoh’s heart became hard, and he did not listen to them, just as the Lord had predicted.

The First Blow: Water to Blood

7:14 The Lord said to Moses, “Pharaoh’s heart is hard; he refuses to release the people.