Reflecting the Light

(Jn 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.

Because the followers of Jesus reflect this light, we read that:

(Ps 34:5)MKJV They looked to Him, and were filled with light; and their faces were not ashamed.

(Mt 5:14) Ye are the light of the world. A city that is set on an hill cannot be hid.
(Mt 5:15) Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house.
(Mt 5:16) Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven.

If our light shines then some will see our good works. This is how we shine the light, by holding fast the Word of God (Php 2:16):

(Php 2:14)EMTV Do all things without grumbling and disputing,
(Php 2:15) in order that you may become blameless and harmless, children of God without fault in the midst of a crooked and perverted generation, among whom you shine as light bearers in the world,
(Php 2:16) holding fast the word of life, so that I may rejoice in the day of Christ, that I have not run in vain or labored in vain.

(Ps 119:130) The entrance of thy words giveth light; it giveth understanding unto the simple.

(Ps 119:105) Thy word is a lamp unto my feet, and a light unto my path.

(Pr 6:23) For the commandment is a lamp; and the law is light; and reproofs of instruction are the way of life:

We read about the "illumination of the gospel" in 2Co 4:4, because the Word is the light of the world.

(2Co 4:3)EMTV But even if our gospel is hidden, it is hidden among those who are perishing,
(2Co 4:4) among whom the god of this age has blinded the minds of the unbelievers, so that the illumination of the gospel of the glory of Christ, who is the image of God, should not shine on them.

Further, the Word is a treasure, as we can infer from 2Co 4:7.

(2Co 4:5)EMTV For we preach not ourselves, but Christ Jesus the Lord; and ourselves your servants for Jesus' sake.
(2Co 4:6) For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ.
(2Co 4:7) But we have this treasure in earthen vessels, that the excellency of the power may be of God, and not of us.

The Word is Jesus, who is the light of the world. The Word is the light of the world.