What does it mean that people loved darkness rather than light (John 3:19)?

And this is the thing that God lays to their charge. Light is come into the world, and they have loved darkness because their works were evil. Could there be a more just subject of condemnation? It was no question of their not finding pardon, but of their preferring darkness to light that they might continue in sin.

John 3:19-21. Man's responsibility is based upon the fact that "light is come into the world", and shone in full splendour in the Person of the Son, revealing the heart of God. Man is responsible to avail himself of the light. The fact that he has made himself incapable of doing so does not affect his responsibility. Men love darkness rather than light. But why is this? Because their deeds are evil. Thus, by his evil deeds man has made himself incapable of profiting by the light. A drunkard may drink himself into a condition in which he is unconscious and incapable of fulfilling his duties. Nonetheless he is responsible. Incapacity does not relieve from responsibility.

The evil deeds that men do lead them to hate the light that exposes their deeds and disturbs their conscience. An uneasy conscience makes the light insupportable. He that puts the truth into practice will not fear the light.

The judgment (pure and righteous) is this, that light has come in the person of the Son of God, therefore unmistakable as clear, shining light, but people loved darkness, to which they were accustomed, and under which they preferred to hide their evil deeds.

One who loves darkness hates the light: he cannot endure simple, candid truth, for this would expose the evil of his works, just as one's eyes can hardly endure bright light after being long in darkness.

But if one has nothing to hide, then he does not fear the light. No doubt Nathanael illustrates this in John 1:47-48. Having “no guile,” no deceitful covering up of evil, he could come with confidence to the Lord Jesus. Certainly in coming to Him, one finds himself manifested as he really is, and honesty does not object to this: the person's deeds are wrought in God, that is, as subject to God.

But light is come into the world, and the light makes everything manifest. Here is the judgment, that men do not desire manifestation when their deeds are evil, but love the darkness which conceals them. By turning from the light, they show that they know where the light is — that it bears witness to the conscience, although they are not in it so as to get the good of it. The practises of truth comes to the light, that his deeds may be made manifest as being wrought in God.

This makes the light disagreeable to him. It wakes up his conscience, brings before him the day of manifestation; recalls to his mind his life of truancy from God, his atheistical ways, his love of self, his uncleanness, his folly, disobedience and dissoluteness; puts God in a new, but true, light before him; it condemns his lust and pride and worldliness; it puts him in his rightful place as a poor devil-deceived, sinful, degraded object, a good-for-nothing child of wrath; and this he cannot do with, therefore he turns away from its searching beams. “This is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil” (John 3:19). Men preferred the darkness to the light. The light was hated.

Still though the Son of God had not come to earth with the object of condemning, His presence here did incidentally bring in condemnation, inasmuch as He was the Light, and light makes everything manifest, and so brings all men to the test. Light acts in illumination and manifestation, and in its presence man reacts in one of two ways. If he is a doer of evil he loves darkness and hates light because it reproves him. If a doer of truth he welcomes the light and comes to it. These verses (18-20) assume that "he that believes on Him" is the doer of truth; whilst "he that believes not" is the doer of evil. The one comes to the light and there is no condemnation for him; the other remains in the darkness, and this is sufficient to condemn him. The light has appeared in the coming of the Son of God and he has not believed. That is enough, and there is no need to wait until the arrival of the actual day of judgment. He is condemned already.

155 He, then, that believes in Him shall not be judged, as it is said also in chapter 5 of this same Gospel. He who believes has everlasting life, and he shall not come into judgment. But he that believes not in Him is judged already, because he hath not believed in the name of the only-begotten Son of God. The presentation of the Son of God, of the Word of God, made flesh, had already put man to the test; the question of his state had been resolved, he rejected God in the Person of His only-begotten Son, the full Light; and God is light, as He is love. It is not here sovereign love, but conscience and responsibility. The light has been in the world, and has shone clearly; the light of men, adapted to men. They loved darkness rather than light, because their deeds were evil. Conscience feels the light, but that does not change the will; and if the will remains perverse, conscience makes divine light insupportable. The state of the will, as to God manifested down here, when conscience recognises the light, is that which forms the basis of an existing judgment, present, but final, there where Christ has been thus presented.

But we are now to look at the demoniac's deliverance. "But when he saw Jesus afar off, he ran and worshiped him." That it was not the devil brought him to the feet of Jesus we may be quite sure and we may get in this more than a hint of how the devil's power is exercised over those in whom he works. It is not the direct might and mastery of a superior being. Mere force this way would not be suffered. But even if "the god of this world blinds the mind, lest the light of the glorious gospel of Christ shines in," it is only the minds of "those that believe not," and who thus by the rejection of God's grace and love shut themselves up under Satan's power. It is not that the Word is not witness to itself. It is not that the light shining is not evidence for all. No: the condemnation is that "light is come into the world, and men loved darkness rather than light." Not that they were ignorant that the light was there but they loved and chose darkness. Will was at work, and the heart rejecting. Thus man yields himself up to the devil, and then and thus his blinding power is exercised, until the deluded soul finds perhaps a hundred good reasons for rejecting what he never wanted to receive. How little conscious we are of how the understanding is controlled by the will, and how men may end by becoming "honest infidels" to the truth, who yet never became so in an honest way.

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 light is not darkness, and in God is not one iota of darkness. Light is that which is revealed, and reveals things precisely as they are: it is absolute truth. If man’s works are in the dark, it is because they are false and evil. Men love darkness, because their deeds are evil, and they do not want themselves exposed. True, the light of God is beyond our understanding, but not because of being shrouded in darkness, rather because of its very brightness, as the light of the sun is too bright for eyes to contemplate, while yet the light and warmth of the sun provides wonderful blessing for man. No one would refuse the healthful beams of the sun, simply because he was not able to understand its existence!