What do you listen to?  Is it positive, God-centered things…or does secular music and movies have your attention right now?  This verse stresses that we need to guard what we have heard, ( God’s Word / the Gospel Message) and keep that in front of us when we are tempted to fall back into sin.  And the Lord is good to bring into remembrance all we’ve heard about Him when we are weak, disheartened, or enticed by the world.  For He can fill our mind with truth and drown out Satan’s whispers.