Exodus 8:15,28,29,32
But when Pharaoh saw that there was respite, he hardened his heart, and listened not to them; as the LORD had said.
Nave's Topical Index—AKJV

Exodus 9:27-35
And Pharaoh sent, and called for Moses and Aaron, and said to them, I have sinned this time: the LORD is righteous, and I and my people are wicked.
Nave's Topical Index—AKJV

Exodus 10:8-29
And Moses and Aaron were brought again to Pharaoh: and he said to them, Go, serve the LORD your God: but who are they that shall go?
Nave's Topical Index—AKJV