Proverbs 4:24-27, Man the Bulwarks!
Keep thy heart with all diligence! Here is a paradox! We are commanded to do what we cannot, for no one can keep his own heart. “The greatest difficulty in conversion is to win the heart to God, and after conversion to keep it with Him” (Flavel). It is God’s work, but “our efforts are His instrumentality. He implants an active principle, and sustains the unceasing exercise” (Bridges). We know thoughts shape our character and conduct. Paul’s appeal in Romans 12:1-2 is to every faithful soldier on the Bulwarks.