What is the meaning of John 1:4-5?

4 In him was life; and the life was the light of men. 5 And the light shineth in darkness; and the darkness comprehended it not. (John 1:4-5 KJV)

Thomas Scott

Verses 4-5: The evangelist here further testifies, that “in the Word was LIFE” (even as water is in a fountain or spring, or as light is in the sun), whence it issued forth to animate all orders of living creatures, from the most minute to the most exalted. “And the Life was the Light of men:” all the powers of man’s understanding, and all the information communicated to him from every quarter and by every avenue; all that can be called  light, natural, intellectual, moral, or spiritual, is from “the Word,” and that Fountain of life which is in him; especially he, who is the Life of the universe, is become the Light of fallen men, to show them the way to everlasting life and felicity.—But “this Light shineth in darkness:” men hold the truth in unrighteousness: the discoveries made of the Creator by the words of creation, as addressed to the natural reason and conscience of men, fail of producing a profitable knowledge of God, because of the depravity of the human heart; and notwithstanding this light, the world continues enveloped in darkness and wickedness. The light of Revelation, in the former ages of the world, had shone amidst the darkness, which it had not dispelled: the Gentiles still continued in almost total darkness; and the Jews misunderstood, perverted, or neglected the light. Even the Christian Revelation, though more complete, still shineth as a light in the midst of a dark world, which generally lieth in error, ignorance, and wickedness.—For “the darkness comprehended it not,” or “did not apprehend it.” Fully to comprehend the light which God affords us concerning himself, his truth, and will, may be impossible to a finite creature; but the perverseness to which sin and satan have reduced men, causes them to despise, hate, and reject the light. “They like not to retain God in their knowledge;” they will not take hold of or retain instruction; they do not avail themselves of the light, but close their eyes to it; so that as to numbers it shines in vain. This is the real, and in some sense the only, reason why Christ, “the Light of the world,” hath not by his gospel enlightened all the nations of the earth. But no external revelation can effectually profit an apostate rebellious creature, except it be attended with an internal operation of the Holy Spirit, preparing the vitiated organ to receive the light: And as it seems to have been the design of infinite wisdom, in leaving the nations during so many ages without revelation, to prove by facts what a blind guide man’s boasted reason is; so it appears also to be the purpose of God, to show in the same manner that even Revelation alone will not profit fallen creatures, without the teaching of his Holy Spirit. When these two humiliating truths are undeniably proved, we have ground in scripture to conclude that God will render the light of revelation effectual by his powerful teaching, to “fill the earth with the knowledge of his glory, even as the waters cover the sea.”—The passage under consideration may be applied to all these particulars. The evangelist’s language, however, is very remarkable, and has been considered as the mere effect of inattention to the common rules of grammar.—The first verb is present, “shineth;” the second is in the aorist, which generally denotes the past, “comprehended,” or “apprehended;” but may he not have intended to state that the light of divine truth still shone when he wrote in the midst of a dark world; yet that, during the ages preceding Christ, nay, during his personal ministry, this light had been less apprehended and made use of in the world, than it was after his ascension and the pouring out of the Spirit, and the preaching of the gospel to the Gentiles. Before it shone dimly among the Jews; but then it shone far more clearly both on Jews and Gentiles Isa 60:1-2.