John 9:1-5 – And as Jesus passed by, he saw a man which was blind from his birth. And his disciples asked him, saying, Master, who did sin, this man, or his parents, that he was born blind? Jesus answered, Neither hath this man sinned, nor his parents: but that the works of God should be made manifest in him. I must work the works of him that sent me, while it is day: the night cometh, when no man can work. As long as I am in the world, I am the light of the world.
When the disciples saw the blind man, they asked Jesus who sinned, the man or his parents that he was born blind. Though neither sinned, his blindness was purposed to manifest the works of God (via Jesus healing him). Jesus said that He MUST work the works of Him that sent Him. He said these must be done while it is day, for when the night comes, no man can work.
Now, as Jesus declared, He is the light of the world. The life that is in Him is the light of men (John 1:4-9) and all that follows Him will not walk in darkness (evil, sin), but will have the light of life – righteousness, salvation, eternal life (John 8:12).
There will come a time when the night will come and no man can work. This refers to a future period in history, and for our own lives, it will come upon our death or the Lord’s return. Therefore, we must redeem our time by making the most of each moment we have: