Vanity in the House of God
Qoheleth exhorts you to guard your steps when you go to the house of God, else you risk your coming being nothing but vanity.
Why is that? Because God is holy in the strictest sense of the word. To be holy is to be set apart. When we apply holy to a person we’re talking about that person as being set apart from other people. But when we apply it to God we’re talking about God being set apart from all of creation. He stands over it. The fact that God would choose a place in his creation to call his dwelling place is remarkable. He’s called a consuming fire and shows himself in this way at times. There is the sense that if you draw near to God, the enormity of his presence, would consume you—not because he is evil, but simply because of who he is. So guard your steps.