The Egyptians will know that I am the Lord

Exodus 6:28-7:13
Aaron to speak for Moses: the Lord said to Moses: "See, I have made you like God to Pharaoh, and your brother Aron will be your prophet."
I will lay my hand on Egypt and with mighty acts of judgment I will bring out my divisions my people the Israelites. And the Egyptians will know that I am the Lord when I stretch out my hand against Egypt and bring the Israelites out of it.
Aaron's staff becomes a snake. and the Egyptian magicians also did the same things by their secret arts. But Aaron's staff swallowed up their staffs.
Pharaoh has heard and rejected Moses' request. He has shown the sort of man he is;" Who is the Lord...? I do not know the Lord and I will not let Israel go'.
Now God begins a series of judgments which will teach Pharaoh and his people who the Lord is, and show them the extent of God's power over all creation.
Why?
"God will harden Pharaoh's heart, and though God multiply his miraculous signs and wonders in Egypt, Pharaoh will not listen". Because Pharaoh's heart did not acknowledge the Lord, refused to listen to God's word. He did not afraid God. So God let Egyptians know "Who is the Lord?"
Suffering are caused by their heart and refuse to turn to the Lord.
How?
Listen to the Lord is beginning of blessing and freedom.