Love to Jesus is the basis of all true piety, and the intensity of this love will ever be the measure of our zeal for His glory. Let us love Him with all our hearts, and then diligent labor, and consistent living will be sure to follow.
Outward acts of piety which do not flow from the new and God-given affections of the heart, which delight to depend on God and seek his glory are only legalism and have no value in honoring God.
Author: John Piper Source: The Supremacy of God in Preaching, Baker, p. 83.
A constant attention to the work which God entrusts us with is a mark of solid piety.