In many places in the Bible the word "light" is used to symbolize the Christ, Truth. For example, Isaiah, in his prophecy of the coming of the Messiah, wrote, "The people that walked in darkness have seen a great light: they that dwell in the land of the shadow of death, upon them hath the light shined."
When John the Baptist testified to the fact that Christ Jesus had come into the world in fulfillment of Scriptural prophecy, he said, "That was the true Light, which lighteth every man that cometh into the world." Modern Bible commentators say that the word which in the Authorized Version is translated "cometh," in the original Greek means, literally, "is coming"; and they agree that it was the Light—"which lighteth every man"—that was coming into the world. Thus the passage might be rendered, "That was the true Light, which lighteth every man that cometh [or is coming] into the world." Truly that Light is the Christ, Truth, which Jesus revealed and which he proved to be that which lighteth—enlightens—every man.
Light may be spiritually defined as intelligence, and that intelligence which is a quality of divine Mind, and is at one with that Mind, constitutes true enlightenment, and illumines human consciousness with the understanding of real being. It is in fact the light of Truth; hence it is the Christ. Therefore, when Jesus had reached a certain point in his marvelous ministry to mankind, he was ready to declare boldly, referring to his spiritual identity, "I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life."