How does God speak to you?
Behind the minute laws and rules of a book like Leviticus, are principles which hint at what God is like. He is a Holy God who must be taken seriously. People of that time
(and a lot of today's people) had the habit of inventing and discarding gods as they felt like it. God declares that He alone is the true God, worthy of all worship.
In one sense what God ultimately demands -- OBEDIENCE -- has not changed since Old Testament days. But God teaches the Israelites much as a parent must teach a young child -- with dozens of clearly spelled-out rules.
Time alone to speak with God is essential.