He tried a different way than God had instructed. He followed his own plan instead of following God's plan. He took what God said was His. He tried to live a double life. He was a hypocrite.
Mankind comes up with many plans.
But unless they are God's plan, they are doomed to failure. It may seem reasonable and right to us, but we are not God. We should remember that. In the garden of Eden, Adam and Eve did the same thing. They went another way than the one God told them to.