The heart of the believer should never be sold to the world and Satan. In Proverbs 4:23 we see that we must put effort into keeping our heart as we seek the Lord and His ways.
Words matter. Do we consider our words or just speak what comes to mind? James challenges us in James 3 with our need to control the tongue, to be careful what goes into our heart. We may change someone’s eternity because of our words!