One old dictionary that I had (I regret not knowing what happened to it) one definition for Holy: to be different. we are to be different. Different in our actions, dress, attitude, looks. We are not to be like the world like my Brother Paul says in Romans 12 "do not be conformed to this world, " "do not allow this world to shape you into what it wants you to be."
When we accept Jesus as our Lord and Saviour we are justified, we are as if we had never sinned, we are bathed in the blood of Christ, when Almighty God sees us He does not see us, He does not see our sin, He sees the blood of His Son, we are blameless. Hallelujah to the Lamb.