The first fruit of love is the musing of the mind on God. He who is in love, his thoughts are ever upon the object. He who loves God is ravished and transported with the contemplation of God. “When I awake, I am still with thee” (Psalm 139:18). The thoughts are as travelers in the mind. David’s thoughts kept heaven-road. “I am still with Thee.” God is the treasure, and where the treasure is, there is the heart. By this we may test our love to God. What are our thoughts most upon? Can we say we are ravished with delight when we think on God? Have our thoughts got wings? Are they fled aloft? Do we contemplate Christ and glory?… A sinner crowds God out of his thoughts. He never thinks of God, unless with horror, as the prisoner thinks of the judge.
Dallas Willard, The Great Omission: Reclaiming Jesus’s Essential Teachings on Discipleship