I am the Lord.or:
I am the Lord, your God.and a couple of times:
Be holy because I am holy.
First, I think Leviticus is important because it helps us understand Jewish culture and that will be important in understanding future passages.
Second, you can see how God is protecting His people from hurt or damage. Each rule is designed to protect them. He cares deeply.
But more than that, God is showing us that He is Lord. He is sovereign. He rules over all. And He is holy...He is giving them a way to have a relationship with Him by making themselves clean.