(5) As long as I am in the world, I am the light of the world.--Better, when I am in the world. The thought is that the two things necessarily co-exist. He is the true Light, and this true Light cannot be in the world without shining in its darkness. (Comp. Note on John 1:5.) The thought is here closely connected with His teaching in the Temple but a short time before (John 8:12, "I am the Light of the world"), and also with the removal of physical and spiritual darkness which immediately followed.

Verse 5. - While - or, whensoever - I am in the world, I am the Light of the world. He had said (John 8:12), "I am the Light of the world: he that followeth me shall not walk in darkness." He was sublimely conscious of his power to do for the moral world what the sun was doing for the physical world. He was the Occasion of its life, the Condition of its activity, the means of its instruction, the Source of all its beauty, its joy, and its progress. The ὅταν, which is translated quamdiu in the Vulgate, and "so long as" in the Authorized Version, means strictly "whensoever," and refers to the entire period of his activity (see John 1:5). But while the sun of this world cannot open the eyes of the blind, and wastes his radiance on their sightless sockets, so, unless Christ were more than the sun, and could give the power as well as the opportunity of seeing, he would never have done the work of him that sent him. The fact that he is the Light leads him to remind the disciples that he is the true Source of eyesight as well as of the conditions of vision. Light enough for all the world shines into the darkness, but the darkness comprehendeth it not. This Jewish people are surrounded by floods of light. The spiritual world stands revealed fully to Christ's own gaze. But mankind hates the light, loves darkness on these matters rather than the light. There is a radical fundamental change that must come over men, or they will never see. This evil, this terrible calamity that has befallen man, will vitiate all the provision of mercy. There must be a new beginning, a new birth, a work of God wrought in men, as well as a sublime revelation made to men, or the whole mission of the Christ would be incomplete.

9:1-7 Christ cured many who were blind by disease or accident; here he cured one born blind. Thus he showed his power to help in the most desperate cases, and the work of his grace upon the souls of sinners, which gives sight to those blind by nature. This poor man could not see Christ, but Christ saw him. And if we know or apprehend anything of Christ, it is because we were first known of him. Christ says of uncommon calamities, that they are not always to be looked on as special punishments of sin; sometimes they are for the glory of God, and to manifest his works. Our life is our day, in which it concerns us to do the work of the day. We must be busy, and not waste day-time; it will be time to rest when our day is done, for it is but a day. The approach of death should quicken us to improve all our opportunities of doing and getting good. What good we have an opportunity to do, we should do quickly. And he that will never do a good work till there is nothing to be objected against, will leave many a good work for ever undone, Ec 11:4. Christ magnified his power, in making a blind man to see, doing that which one would think more likely to make a seeing man blind. Human reason cannot judge of the Lord's methods; he uses means and instruments that men despise. Those that would be healed by Christ must be ruled by him. He came back from the pool wondering and wondered at; he came seeing. This represents the benefits in attending on ordinances of Christ's appointment; souls go weak, and come away strengthened; go doubting, and come away satisfied; go mourning, and come away rejoicing; go blind, and come away seeing.As long as I am in the world,.... Which had been now two or three and thirty years; but was not to be much longer.

I am the light of the world; See Gill on John 8:12. Though doubtless he said this with some view to the cure he was about to perform, it being agreeable to his character and work, while he was in the world.