What is light according to the Bible?

In the same way that God did not define life, eternal life, for us in a dictionary, so the Lord Jesus did not give a verbal definition of light. God is light - it is part of His essential nature. It indicates His intrinsic and absolute purity. 'Light is immaterial, diffusive, pure and glorious. It is the condition of life. Physically, it represents glory; intellectually, truth; morally, holiness.' (M.R. Vincent) It is what God is in Himself in an absolute sense. Flowing from it are His attributes - which are relative - such as righteousness and holiness. His attributes are a consequence of what He is in Himself; they indicate what He is in relation to others.

As to light — who can define it? Men have formulated theories to account for the light of creation, but they cannot really explain it. Who then shall explain the uncreated Light? We know that light is necessary if life is to exist in any but its lowest forms. We know that it is healthful, that it illuminates and exposes all things, and that if it enters darkness flees. In God there is no darkness at all, for darkness stands for that which is removed from the action of light, that which is hidden and sinful.

Light is invisible in itself, but makes everything visible; it is so defined in Ephesians 5:13. It is more than the "offspring of heaven firstborn," for it is the very image-name of God Himself. God is light.

Besides the references to physical light as existing distinct from the sun, and then emanating from the sun as the great light-bearer, the term is mainly used in scripture in a moral sense. Light from God is His word revealing Himself, and not only making manifest the dangers here, but acting as a lamp in showing the true path. Ps. 119:105. The Psalmist asked Jehovah to lift upon him the light of His countenance ( Ps. 4:6 ), and declared that Jehovah Himself was his light, Ps. 27:1. As natural light brings vigour and health to the body, so the light of God gives cheerfulness and strength to the soul.

The light-giving function is at its highest and most appropriate use in the tabernacle, where it reveals all the relations between God and His people, but of course its use is universal. That was the true light, which (lit.) coming into the world lights every man. That of Galilee, and not — for example — Buddha, though his name signifies the Enlightened One, nor even Moses, though he gave an anticipatory reflection of that light, as a mirror might. What literal darkness, with its sins and doubts, its fears, perils, and lurking evils, is to the outward man, spiritual darkness — ignorance, prejudice, evil — is to the inward man. Light is knowledge; which seems a very meagre definition, but it is beautiful in itself as well as in what it discloses and creates. For it discloses loveliness as truly as deformity, and not only discloses but creates all the beauties of colour that deck the gorgeous universe. Light, which is the primal work of creation and which is a symbol of God Himself, is of so mysterious a nature that even though we find out year by year more about it, yet we do not know even now for certain what it is, — whether for instance it be an element that travels to us from the heavens, or the vibration of some omnipresent ether, impalpable and all-pervading. None can understand it, but all can benefit by it. Each decade brings us some fresh discovery concerning it. Its susceptibility to sound; its power to produce sound; its power to reproduce form; its actual physical power to move bodies, as shown by the radiometer; its power to draw the tender shoot of the plant above the black earth; and when the darkness is doing its deadly work of producing poisonous carbonic acid gas from its leaves, the light suddenly appears, stops it, and in its turn produces the life-giving oxygen.

By light, I mean the knowledge of God, for the measure in which the heart of any man is in the light is the measure in which he has learned God. “God is light, and in Him is no darkness at all.” This can be said now that He has been declared, for in Christ He has come out of the thick darkness into the light of revelation. Jesus could say, “I am come a light into the world that whosoever believes on Me should not abide in darkness” (John 12:46). When Christ, the true Light, is received into the soul the darkness has passed away forever, and it is then that one begins to get right thoughts about every moral and spiritual question.

The light is the revelation of God, and whoever receives that light by faith in it has got the knowledge of God in grace and love. The light is for men that are in darkness. Where the light is received the darkness is dispelled; then the soul requires instruction in the mind and will of Him with whom he is set in entirely new relationships: he wants instruction in the truth; and in turn, he becomes a light in the midst of this world's darkness. Light shows me things as they really are, but when I know the truth I see how different everything on earth is to that which it should be. So that the truth may be said to be light. "Thy Word is a lamp to my feet, and a light to my path" (Psalm 119:105). The light of the Gospel shows one how thoroughly under the power of Satan he has been. Christ is both the truth and the light. They are very near akin.

Light is here also as always, the revealing power: "that which doth make manifest is light." (Eph. 5:13). But the "fruit of the light is in all goodness and righteousness and truth" (ver. 9); and the apostle, when showing how eternal life, or the divine nature, is exhibited in those that are born of God, makes its display to be in righteousness and love: "whosoever doeth not righteousness is not of God, neither he that loveth not his brother" (1 John 3:10).

Toward the middle of man's night God raised up a great light for the people which sat in darkness, and for them which sat in the region of the shadow of death, light sprang up. He sent His Son into this world, and in His Son was life, and the life was the light of men. This true light so bright and resplendent, was that which, coming into the world, lighted every man; but the darkness, by which the mind of man is blinded through sin, comprehended it not. Alas, it was wilful blindness on his part. The Lord tells out the secret of it, "Light is come into the world, and men loved darkness rather than light, because their deeds were evil."

But the Spirit is not seen: it is the light that is seen, for light is both revealed and revealing. In the light everything is manifested as it really is. And natural light is beautifully symbolic of the Lord Jesus Christ, who said, "I am the light of the world: he that followeth Me shall not walk in darkness, but shall have the light of life" (John 8:12). Therefore, in Christ we see God revealed as He really is, and the light of His face fully reveals us also. Such is the first great work of the Spirit of God with our souls, in the marvel of our being brought from darkness to light, from the power of Satan to the living God.