Worship is a way of gladly reflecting back to God the radiance of His worth. It is not a mere act of willpower by which we perform outward acts. Without the engagement of the heart, we do not really worship. The engagement of the heart in worship is the coming alive of the feelings and emotions and affections of the heart. Where feelings for God are dead, worship is dead.
True worship must include inward feelings that reflect the worth of God's glory. If this were not so, the word hypocrite would have no meaning. But there is such a thing as hypocrisy - going through outward motions (like singing, praying, giving, reciting) that signify affections of the heart that are not there. "This people honours me with their lips, but their heart is far from me."
- John Piper, from Desiring God, p 87-88
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