Exodus 3:19, 20
"But I am sure that the king of Egypt will not let you go, no, not even by a mighty hand. So I will stretch out My hand and strike Egypt with all My wonders which I will do in its midst; and after that he will let you go."
I would like to share a piece from Charles Stanley's Life Principles on this verses:
"Pharaoh is probably the best illustration in the Bible of a person with a hard heart. He thus provides a blueprint for what happens when a person refuses to accept and bend his or her will to the truth of God.
Pharaoh receive overwhelming evidence-plague after plague, sign after sign, miracle after miracle-and still refused to let the Israelites go. Even when faced with undeniable evidence of his error, Pharaoh refused to acknowledge that another was greater than he. In the end, his pride and hard-heartedness cost him his army and almost his kingdom.
All of us have stubbornly desired to have things the way we want them, even when our way opposes God's way. Every time we say no to God, we skirt the edges of rebelling once too often. If we repeatedly say no to God, then like Pharaoh we may develop a hard heart that leads to destruction."
Make it a point to say "yes" to God daily.