A young boy practiced his lines for the Sunday school program, but when the time came for the performance in front of the congregation, he drew a blank. Moments passed as he tried to remember his part. His mother was perched on the front row and tried gesturing to him to prod his memory. She finally whispered the words her son had rehearsed–“I am the light of the world!” When the little fellow heard his cue, he smiled and with renewed confidence proclaimed, “My mother is the light of the world!”
In case we draw a blank about this profound statement, the original quotation is found in John 8:12. In one of His several “I am” statements, the Lord Jesus affirmed,
“I am the light of the world. He who follows Me shall not walk in darkness, but have the light of life.”
Let’s consider the significance of Christ’s role as this Light and how His people share in His ministry of radiance.
When Jesus made His declaration as the Light of the world, He was probably alluding to a Jewish custom of the day. Adam Clarke observed, “…the Jews added a ninth day to this feast [of Tabernacles], which day they termed, The Feast of Joy for the Law; and on that day they were accustomed to take all the sacred books out of the chest where they had been deposited, and put a lighted candle in their place, in allusion to Proverbs 6:23: ‘For the commandment is a LAMP (or CANDLE) and the law is life’ (Cf. Ps. 119:105).”  If The Holy Scriptures are a source of spiritual light, how much more is Jesus Himself, “for the testimony of Jesus is the spirit of prophecy” (Rev. 19:10 Cf. Heb. 1:1-3).
When Jesus declared “I am the light of the world,” He was identifying Himself as the promised Messiah. The Old Testament prophesied that the Anointed One would be a “light to the Gentiles” (Isaiah 49:6-7). Malachi predicted, “But to you who fear My name The Sun of Righteousness shall arise With healing in His wings…”(Mal. 4:2). This expectation was confirmed by Zecharias–the father of John the Baptist–who gave thanks for the tender mercy of our God,
With which the Dayspring from on high has visited us;
To give light to those who sit in darkness and the shadow of death,
To guide our feet into the way of peace” (Luke 1:78-79).
The New Testament further identifies Christ as the unique Light. “In Him was life, and the life was the light of men. And the light shines in the darkness, and the darkness did not comprehend it” (John 1:4-5). The Lord Jesus summoned people to receive His testimony: “A little while longer the light is with you. Walk while you have the light, lest darkness overtake you; he who walks in darkness does not know where he is going. While you have the light, believe in the light, that you may become sons of light” (John 12:35-36).
Although Christ’s ministry as the Light of the world was expressed uniquely during His first Advent, He continues as the source of light to those who receive Him. As the apostle Paul wrote, “For it is the God who commanded light to shine out of darkness, who has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ” (2 Cor. 4:6).
When by grace through faith we receive Christ as our Lord and Savior, we experience a spiritual rebirth (John 3:3; Titus 3:5-6). This regenerating work of the Holy Spirit gives new life to the believer (2 Cor. 5:17). I believe the locus of this change is the human spirit: “The spirit of a man is the lamp of the LORD, Searching all the inner depths of his heart” (Prov 20:27). Although this “lamp” was extinguished at the Fall (Rom. 5:12), at salvation it is rekindled (Cf. 1 Cor. 6:17; 2:14). Notice how the New Testament refers to the believer’s essential spiritual nature: “For you were once darkness, but now you are light in the Lord. Walk as children of light” (Eph. 5:8; Cf. 1 Thess. 5:5; 2 Cor. 6:14).
As ones who are spiritually united with Christ–the Light of the world–we are called to be separate: “Do not be unequally yoked together with unbelievers. For what fellowship has righteousness with lawlessness? And what communion has light with darkness?” (2 Cor. 6:14).
We can have a luminous influence on this dark world as we live as representatives of the Kingdom of God. “And have no fellowship with the unfruitful works of darkness, but rather expose them… But all things that are exposed are made manifest by the light, for whatever makes manifest is light” (Eph 5:11,13).
As those who are indwelt by the Light of the world, believers should faithfully reflect the reality of Christ to others. This is the kind of ministry John the Baptist had: “This man came for a witness, to bear witness of the Light, that all through him might believe. He was not that Light, but was sent to bear witness of that Light” (John 1:7-8). In the Sermon on the Mount, Christ used two comparisons to describe our testimony as lights: “You are the light of the world. A CITY that is set on a hill cannot be hidden. Nor do they light a LAMP and put it under a basket, but on a lampstand, and it gives light to all who are in the house” (Matt 5:14-15). Therefore, He summons us, “Let your light so shine before men, that they may see your good works and glorify your Father in heaven” (Matt 5:18).
Charles H. Spurgeon exhorts us to let our light shine a a means of guidance, warning, and encouragement to others:
A Christian man should so shine in his life, that a person could not live with him a week without knowing the gospel. His conversation should be such that all who are about him should clearly perceive whose he is, and whom he serves; and should see the image of Jesus reflected in his daily actions. Lights are intended for GUIDANCE… We are to point sinners to the Saviour, and the weary to a divine resting place. Men sometimes read their Bibles, and fail to understand them; we should be ready, like Philip, to instruct the inquirer in the meaning of God’s Word, the way of salvation, and the life of godliness. Lights are also used for WARNING. On our rocks and shoals a lighthouse is sure to be erected. Christian men should know that there are many false lights shown everywhere in the world, and therefore the right light is needed … Lights also have a very CHEERING influence, and so have Christians. A Christian ought to be a comforter, with kind words on his lips, and sympathy in his heart; he should carry sunshine wherever he goes, and diffuse happiness around him.
Eliza Hewitt was a school teacher in Philadelphia, Pennsylvania in the late 1800’s. An injury required her to be in a cast for six months. When the cast came off, she celebrated her recovery with a walk in the park. This stroll inspired her hymn, Sunshine in the Soul. The chorus testifies,
O there’s sunshine, blessed sunshine,
When the peaceful, happy moments roll;
When Jesus shows His smiling face,
There is sunshine in the soul.” 
Bask in the inner sunshine of His presence. Abide in Christ and the Light of the world will shine through you!
 “Adam Clarke’s Commentary” – (John 8:12; Cf. John 7:37), rabbinic source: Buxtorf. Synagog. Jud. c. xxi.
 Quoted in Acts 13:47; Cf. Isa 9:6; 42:6-7)
 Charles H. Spurgeon, “Morning and Evening” (September 6 am reading).
 Eliza Edmunds Stites Hewitt (1851-1920) in “Glad Hallelujahs,” by William Kirkpatrick and John Sweney (Philadelphia, PA: Thomas T. Tasker, Sr., 1887).
Revised edition. Copyright 2011 by John B. Woodward. Permission is granted to reprint this article in its entirety for non-commercial use with credit given.Biblical quotations are from the New King James Version, Copyright 1982by Thomas Nelson.