Jesus quoted Isaiah in Matthew 15:9-10
“‘This people honors me with their lips, but their heart is far from me; in vain do they worship me, teaching as doctrines the commandments of men.’”
John Piper preached a sermon, “Worship is an End in Itself” based on this passage, and here is the concluding paragraph. He said, “Only worship is an end in itself. Only worship should not be done as a means to achieving something other than itself.”
In conclusion, by way of summary, Jesus said, “This people honors me with their lips, but their heart is far from me.” Therefore, even though worship can refer to a form of activity in which the heart is distant, yet true worship which delights God is the drawing near of the heart to God, or, to put it another way, the quickening of the heart with genuine feelings in response to God’s glory. Such feelings are never performances of will power calculated to accomplish other ends. They are ends in themselves. Therefore, since they constitute the heart of genuine worship, worship is an end in itself. And our Sunday morning service is unique in its focus on God who is greatly honored in such worship. And it is for his name’s sake that I ask you all very earnestly to take time Saturday night and Sunday morning to prepare yourselves to meet him here, praying with the psalmist, “Open my eyes that I might behold wondrous things in your word” (Palm. 119:18). And: “Unite my heart to fear thy name” (Psalm 86:11).