2 Samuel 23:4 - And He shall be as the light of the morning, when the sun rises, even a morning without clouds; as the tender grass springing out of the earth by clear shining after the rain

Revelation 22:16 - I Jesus have sent my angel to testify unto you these things in the churches. I am the root and the offspring of David, and the bright and morning star. 

Jesus is often referred to as the light of the world. Just as the sun lights and heats our physical world, the Son of God gives our spiritual life the light and warmth we need to grow.