What we do in worship reveals what we think about God. A church that worships through dry and joyless ritual shows that it believes in an absent God. A church that stirs up emotional enthusiasm and fills the worship service with entertainment believes in a week God who needs our spiritual help. A church focused on money reveals a God who is unable to meet our needs, whereas a church that exalts its own celebrities shows its blindness to the glory of God.
But what does it say when people reverently lift their hearts in praise? It says they think God is worthy and great. What do Christians show when they humbly confess their sins? They show that they believe in a holy and forgiving God. What does it say when we commit ourselves to prayer? It says that we believe in a God of power and love. What does it say when Christians are devoted to the reading and teaching of God’s word? It shows our belief that God has reveal himself, that his Word is truth, with power to save. What does a church say by worshiping according to the Bible instead of the latest worldly fad and fancy? It says that God matters more than worldly approval and that his ways are trust worthy and right.
-Rick Phillips, from Reformed Expository Commentary: John.