A Jesus-follower’s mind is to be filled with things above: God’s will, his gifts, his character, his plans for us. People who have been connected to Christ, who have undergone the Great Transition (who have received God’s own life through his Spirit), have God on their minds. The most noticeable difference between the spiritually strong and the spiritually weak is that the strong think more about God. Much more. He is frequently on their minds. I suspect that if the average Christian used half the time he normally spends thinking about entertainment to think about God, he would be a spiritual force on the earth. His life would be revolutionized. He would experience greater purpose, deeper peace and fuller joy.
There is a great story in David McCullough’s book, Truman. One evening when he was president, Mr. Truman decided to take a walk on the Memorial Bridge across the Potomac. In the course of his walk, the “Show Me State” president became curious about how the middle span of the bridge was raised, so he decided to find out. He went across one of the catwalks (can you imagine a president doing such a thing now?) and through the inner workings of the bridge, and suddenly came upon the bridge tender, who was sitting down, eating his evening meal out of a tin bucket.
The man showed absolutely no surprise that the president of the United States was suddenly standing next to him in his secret place on the bridge. He just swallowed his food, wiped his mouth, smiled and said, “You know, Mr. President, I was just thinking of you.”
Truman loved that. He told that story again and again.
When Jesus comes to take us home, perhaps unexpectedly, wouldn’t it be great if we could say, “You know, Lord, I was just thinking about you.”
That won’t happen by accident. We must make a decision to have God constantly present to our minds. We can support that decision by listening to Christian music during the day, by reading or listening to good biblical teaching, by taking in sections of Scripture through study and memorization. If we fill our minds with the ideas that Jesus himself thought and expressed, we will make a place for God to dwell. If we seek things above, Colossians 3:1, our mind, Colossians 3:2, will certainly be set on them.
 David McCullough, Truman (New York: Simon and Schuster, 1992), 623