(Joh 3:19) And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil.
Here is the judgment of God, and why this judgment looms over sinners: men 'love' darkness. To 'love' here means 'take pleasure in, long for , to welcome, to entertain, to be fond of, to love dearly'. This love goes down deep and has a firm grasp on every sinner. Commentary from David Guzik says it nicely, "What keeps people from belief in Jesus and salvation? It is sin, or is it unbelief? Really it is both, because people will not believe because they love their sin." This is from Matthew Henry, "Wretched man is in love with his sickness, in love with his slavery, and will not be made free, will not be made whole. [3.] The true reason why men love darkness rather than light is because their deeds are evil. They love darkness because they think it is an excuse for their evil deeds, and they hate the light because it robs them of the good opinion they had of themselves, by showing them their sinfulness and misery." Christ and His gospel exposes the sins of man, confronts the sinner straightforward and demands him/her to leave their sins. They must part with what it is they love the most. They are confronted by God and His Christ concerning their heinous rebellion and they will never part from this natural love of sin apart from God's mercy and power bringing them to Himself.
Coming to the light condemns the sinner, for their deeds are evil. They know their deeds are evil so they avoid the light, thus, they think they can avoid condemnation. The conscience testifies against them, so they silence their conscience. Creation cries out against sinners, so they deny the Creator and uphold a lie - evolution. Sinners know murder is a sin, so they slaughter the unborn for the sake of 'women's rights'. Sinners know homosexuality is wrong, so they call it 'gay'. Sinners know marriage is supposed to be a man and a woman, so they re-define marriage and usurp the authority of the most High God. Sinners know idolatry is wrong, so they suppress the truth of God's word and fashion multiple 'gods' to worship, including the 'god' of self. Sinners love their darkness - and the more they suppress God's truth, the deeper into that darkness they go. They will never come to the light; to Christ and His gospel truth, 'lest his deeds should be reproved' [vs. 20] - or ' reprove, rebuke, discipline, expose, show to be guilty'
Here is the Thayer Definition of 'reproved':
1) to convict, refute, confute
1a) generally with a suggestion of shame of the person convicted
1b) by conviction to bring to the light, to expose
2) to find fault with, correct
2a) by word
2a1) to reprehend severely, chide, admonish, reprove
2a2) to call to account, show one his fault, demand an explanation
2b) by deed
2b1) to chasten, to punish
The sin nature does NOT want to be confronted by a thrice holy God. The doctrine of 'free will' refuses to acknowledge this truth. Sinners will never come to Christ because the will of man is bent on darkness and hates the light.
This is why earlier in this chapter the Lord told Nicodemus 'ye must be born again'. It is this new birth, being 'born from above' that enables the sinner to 'see', to comprehend, understand, discern Christ and His gospel.
May it please the Lord to save sinners this day.