{4} 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.

(4) The world, which is blind in itself, cannot come to have any light but in Christ alone.

People's New Testament

8:12 I am the light of the world. He then began his discourse to the people assembled. See notes on Mt 5:14 Joh 1:7-10.

Wesley's Notes

8:12 He that followeth me shall in nowise walk in darkness - In ignorance, wickedness, misery: but shall have the light of life - He that closely, humbly, steadily follows me, shall have the Divine light continually shining upon him, diffusing over his soul knowledge, holiness, joy, till he is guided by it to life everlasting.

Scofield Reference Notes

Margin world

kosmos = mankind. See Scofield Note: "Mt 4:8".

Jamieson-Fausset-Brown Bible Commentary

Joh 8:12-59. Further Discourses of Jesus-Attempt to Stone Him.

12. I am the light of the world-As the former references to water (Joh 4:13, 14; 7:37-39) and to bread (Joh 6:35) were occasioned by outward occurrences, so this one to light. In "the treasury" where it was spoken (see on [1804]Joh 8:20) stood two colossal golden lamp-stands, on which hung a multitude of lamps, lighted after the evening sacrifice (probably every evening during the feast of tabernacles), diffusing their brilliancy, it is said, over all the city. Around these the people danced with great rejoicing. Now, as amidst the festivities of the water from Siloam Jesus cried, saying, "If any man thirst, let him come unto me and drink," so now amidst the blaze and the joyousness of this illumination, He proclaims, "I AM THE Light of the world"-plainly in the most absolute sense. For though He gives His disciples the same title, they are only "light in the Lord" (Eph 5:8); and though He calls the Baptist "the burning and shining light" (or "lamp" of his day, Joh 5:35), yet "he was not that Light, but was sent to bear witness of that Light: that was THE TRUE Light which, coming into the world, lighteth every man" (Joh 1:8, 9). Under this magnificent title Messiah was promised of old (Isa 42:6; Mal 4:2, &c.).

he that followeth me-as one does a light going before him, and as the Israelites did the pillar of bright cloud in the wilderness.

but shall have the light of life-the light, as of a new world, a newly awakened spiritual and eternal life.

Matthew Henry's Concise Commentary

8:12-16 Christ is the Light of the world. God is light, and Christ is the image of the invisible God. One sun enlightens the whole world; so does one Christ, and there needs no more. What a dark dungeon would the world be without the sun! So would it be without Jesus, by whom light came into the world. Those who follow Christ shall not walk in darkness. They shall not be left without the truths which are necessary to keep them from destroying error, and the directions in the way of duty, necessary to keep them from condemning sin.