Because what you give your attention to is the person you become. Put another way: the mind is the portal to the soul, and what you fill your mind with will shape the trajectory of your character. In the end, your life is no more than the sum of what you gave your attention to.

John Mark Comer, The Ruthless Elimination of Hurry: How to Stay Emotionally Healthy and Spiritually Alive in the Chaos of the Modern World