From Paul Tripp:
Worship is not first an activity. No, worship is first a position of the heart. It’s only when my heart esteems God above everything else, that I’ll serve him with my time, energy, money, and strength. Impurity of the heart is not primarily about bad thoughts or bad desires. No, impurity of the heart is really about love for something in the creation replacing love that I was only ever meant to have for the Creator. And when I love something in creation more than I love God I’ll think, desire, say, and do bad things.
Now, what all of this means is that our biggest, most abiding, most life-shaping problem exists inside of us and not outside of us. What we actually need to be rescued from is us. What needs to be transformed in our lives is not so much our situation and relationships (although they need transformation as well). What really needs to be transformed are our hearts. What we need are hearts that are clean, that are single-focused in their allegiance to God and His glory. We need grace to transform what we love, what we crave, and what we serve. And what’s the bright and golden promise of the cross of Jesus Christ? It’s a new heart!