Genesis 1:14-16: “And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years: And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so. And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also.”
The sun being the “greater light” and the moon the “lesser light” speaks of Christ and His relationship to the church. As the moon reflects to the earth the greater light of the sun, so the church reflects the greater light of Christ to the world, thus becoming a lesser light herself. So both Christ and the church bear the title “the light of the world”
John 8:12: “Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life.”
Matthew 5:14: “Ye are the light of the world. A city that is set on an hill cannot be hid.”