Do you know who you’re talking to?
God doesn’t ask the question. He doesn’t want to need to, so he reminds Israel of who He is repeatedly in Leviticus (about 283 times). Only Exodus comes close to matching this number, and only Jeremiah and Ezekiel exceed it.
Beginning in Leviticus 17, God elaborates on the ten commandments. As the elaborations unfold, he ends each with “I am the Lord.” It is His reason and explanation behind every command. He gives no further detail.
I remember my mother, when she would tell me to do something and I would ask “why?” Sometimes, she would explain. But often, her answer was “Because I said so.” Her point was: ‘My word is law. You will do as you are told.’ That’s about the size of God’s repeated statements here.
God deals with worship, sexual behavior, and in chapter 19, a variety of diverse areas in life. From specifics about how to worship, to directions mandating charity toward the needy, to how we treat our employees, to the clothing we wear, to honesty in business to what we eat and who we have sex with: God has rules about everything. The important point is, God wants to be involved in every aspect of our lives, and there is nothing about our lives that He doesn’t have an interest in.
He has a right to this intrusiveness. After all, He is “the Lord.”