God is high above us, and so much greater than us. It is this fact that draws us to our knees in humble worship. I've heard it said, "I know two things for sure: There is a God, and I am not him." Check out these devos about God's holiness below.
The Holiness of God: "Set-Apart-Ness"
The Holiness of God: How the Angels Respond
The Holiness of God: Holy Service