Keep a song in your heart.
Light may represent our relationship with Christ. It's in the Bible, Matthew 5:15-16, TLB. "Don't hide your light! Let it shine for all; let your good deeds glow for all to see, so that they will praise your heavenly Father."
Light may represent the effect of our life on others. It's in the Bible, Mark 4:21, TLB. "Then He asked them, 'When someone lights a lamp, does he put a box over it to shut out the light? Of course not! The light couldn't be seen or used. A lamp is placed on a stand to shine and be useful."
Jesus is the light. It's in the Bible, John 1:4-5, NIV. "In Him was life, and that life was the light of men. The light shines in the darkness, but the darkness has not understood it."