If people's thinking is controlled by the sinful self, there is death. But if their thinking is controlled by the Spirit, there is life and peace. Rom 8:6
Your heart is a fertile greenhouse ready to produce good fruit. Your mind is the doorway to your heart—the strategic place where you determine which seeds are sown and which seeds are discarded. The Holy Spirit is ready to help you manage and filter the thoughts that try to enter. He can help you guard your heart.
He stands with you on the threshold. A thought approaches, a questionable thought. Do you throw open the door and let it enter? Of course not. You "fight to capture every thought until it acknowledges the authority of Christ" (2Co 10:5 PHILLIPS). You don't leave the door unguarded. You stand equipped with handcuffs and leg irons, ready to capture any thought not fit to enter.
Just Like Jesus (Max Lucado)