Exodus 9:13-14

Then the LORD said to Moses, “Rise early in the morning and stand before Pharaoh, and say to him, ‘Thus says the LORD God of the Hebrews: “Let My people go, that they may serve Me, for at this time I will send all My plagues to your very heart, and on your servants and on your people, that you may know that there is none like Me in all the earth.