"Every faculty you have, your power of thinking or of moving your limbs from moment to moment,
is given you by God. If you devoted every moment of your whole life exclusively to His service,
you could not give Him anything that was not in a sense His own already."
C. S. Lewis, Mere Christianity
"The earth is the Lord’s, and everything in it, the world, and all who live in it."
Psalm 24.1
We are only stewards of the blessings God has bestowed. We return tithes and offerings as one way of acknowledging His goodness and to participate in sharing His blessings with others.