God is calling, not just to Christmas but to our eternal home with Him. So we are people in exile who can’t see God but hear Him calling, “You shall be holy, for I am holy.” Holiness describes the inmost nature of God, His transcendent perfection. God’s being, His holiness, is not simply an intellectual concept to be grasped. It can’t be anyway. What God’s holiness should produce in us is an emotional reaction, fear. This is not slavish fear. This is not cowering fear. Nor should His coming lead to the opposite extreme, flip familiarity before God. Advent fear is an awe, a reverence, a shut-me-up stillness at (1) the holiness of God but (2) especially that the Holy One comes to us in His Son and teaches us to call Him “Father.” We will come before God at our last heartbeat, a fearful thought, but the fear of Advent is our amazement that He already is coming to greet us, to greet us like the father greeted his prodigal son, coming to us while we are still on the way, coming to us in Jesus. “You shall be holy, for I am holy.”