The apostle Paul speaks a great deal about the importance of the mind in the Christian life. For example, he contrasts the mind set on the flesh with one set on the Spirit. The former, he tells us, leads to death, while the latter leads to life and peace (Rom. 8:5-6). He admonishes us not to be conformed to this world, but to be transformed by the renewal of our minds (Rom. 12:2). Elsewhere he urges us to set our minds “on things that are above, not on things that are on earth” (Col. 3:2).
The mind is the Christian’s battleground. What we choose to do with it, how we choose to employ it, determines everything. Sin begins first with the suggestion, proceeds to the imagination, from there to desire, then to the deed, then to the habit, and finally to destruction. We must resist at the point of suggestion. We cannot always prevent the suggestion from arising—whether it arises from the world, the flesh, or the devil is immaterial—but we can (by God’s grace) refuse to entertain it, refuse to dwell upon it. A wise old preacher once said, “You can’t prevent a bird from flying over your head, but you can prevent it from building a nest in your hair.”
If we don’t deal with sinful thoughts at the point of suggestion, once we allow them to enter the imagination, they become increasingly difficult to resist. The thing to do is not seek to empty the mind of sinful thoughts, but to fill it with worthy ones. Paul says in yet another place,
Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things (Phil. 4:8).