Little children love to ask “why?” The problems with giving an answer are many. First, children have a limited ability to reason. The ability does not begin to take shape until a child is well into his twenties. Second, in order for reasoning to work, there must be knowledge and an experiential basis for that knowledge. Children, by virtue of their lack of both, are poor candidates for reason.
That doesn’t mean, of course, that you shouldn’t try. Correct reasoning takes practice and children should be taught the correct basis for doing it.
But sometimes, you just want to say: “Because I said so.”
My mother was good at reasoning and helped us learn to do it, considering evidence and learning to follow where it lead. But sometimes, either because we failed to understand the process or because she knew we were just wearying her with the hope she would change her view, she would reply: “What did I say? That’s what I mean.”
The argument was closed.
In Leviticus, more than in any other book of the Old Testament, the basis for God’s law is: “Because I said so.” It is expressed, beginning with chapter 18, with the words “I am the Lord your God.” God doesn’t take time to reason through the “whys” of these laws. He simply says: “This is the way it is.”
Something you should not miss is how the chapter opens: ‘Don’t live like the people in Egypt live. Don’t live like the people in Canaan live.’ In other words, when you read the laws of chapter 18, you should understand that both the people of Canaan and Egypt were living in violation of these morals. It is one of the reasons God required his people to leave and stay out of Egypt, and one of the reasons he required the expulsion or extermination of the people of Canaan.
The morals themselves are self-explanatory. The thing to remember is no one engaging in these prohibited practices is allowed community with God or His people, because, God is the Lord, our God..