God told Moses " I am the Lord" and I appeared to Abraham, Isaac, and Jacob as God Almighty, but by my name LORD (YHWH in Hebrew), I did not make myself known to them." (6:2,3) A name is familiar, it is personable, God was coming to Moses in a personal way. The Lord by this let Moses know that He was a God that could be related to personally.
God sent Moses and Aaron to Pharaoh to demand on His behalf that Pharaoh let His people go. Pharaoh refused and each time they told Pharaoh what the Lord would then do. Then a series of miraculous signs were performed; Aarons staff changed into a serpent, the Nile and all the water in Egypt turned into blood, then a pestilence of frogs, then gnats, then flies, then the Egyptians cattle die, then boils on the Egyptians skin, the hail that destroyed all the crops except for the wheat, with more plagues yet to come.
Each time Pharaoh's heart was hardened because he and his servants did not fear the Lord. Jesus said to the Jews; "But I said to you that you have seen Me, and yet do not believe." (John.6.36). Seeing is not believing, God is spirit and men are spiritually dead in their trespasses and sins, therefore the fear of the Lord can only come by the Holy Spirit, you must be born again.
God did all of these things in Egypt to demonstrate his power. This reminds me of the gospel. Why the gospel? So that God could demonstrate both his righteousness and His love. "So that He would be just and the justifier of the one who has faith in Jesus." (Rom.3.26).
For the Bible text click on this link: Exodus