Then you will know that I am the LORD: The Hebrew word translated know is always about experience and relationship. This word also describes human sexual relations. To know God as the LORD means more than just knowing facts about him. It means being in a relationship with him where we continually learn who he is and what he wants us to do.
This is the only true rescue from the human problem of sin described in Genesis 3–11. The idea of knowing the Lord is very important in the book of Exodus. The phrase appears many times, especially in Exodus 5–18 (5:2; 7:5, 17; 8:10, 22; 9:29; 10:2; 11:7; 14:4, 18; 16:6, 12; 18:11).