For whosoever doeth what is evil. The meaning is, that the light is hateful to them for no other reason than because they are wicked and desire to conceal their sins, as far as lies in their power. Hence it follows that, by rejecting the remedy, they may be said purposely to cherish the ground of their condemnation. We are greatly mistaken, therefore, if we suppose that they who are enraged against the Gospel are actuated by godly zeal, when, on the contrary, they abhor and shun the light, that they may more freely flatter themselves in darkness.

That doeth evil - Every wicked person.
Hateth the light - This is true of all wicked men. They choose to practice their deeds of wickedness in darkness. They are afraid of the light, because they could be easily detected. Hence, most crimes are committed in the night. So with the sinner against God. He hates the gospel, for it condemns his conduct, and his conscience would trouble him if it were enlightened.
His deeds should be reproved - To "reprove" here means not only to "detect" or make manifest, but also includes the idea of "condemnation" when his deeds are detected. The gospel would make his wickedness manifest, and his conscience would condemn him. We learn from this verse:
1. that one design of the gospel is "to reprove" men. It convicts them of sin in order that it may afford consolation.
2. that men by nature "hate" the gospel. No man who is a sinner loves it; and no man by nature is disposed to come to it, any more than an adulterer or thief is disposed to come to the daylight, and do his deeds of wickedness there.
3. The reason why the gospel, is hated is that men are sinners. "Christ is hated because sin is loved."
4. The sinner must be convicted or convinced of sin. If it be not in this world, it will be in the next. There is no escape for him; and the only way to avoid condemnation in the world to come is to come humbly and acknowledge sin here, and seek for pardon.

For every one that doeth evil hateth the light - He who doth vile or abominable things: alluding to the subject mentioned in the preceding verse.
The word φαυλος, evil or vile, is supposed by some to come from the Hebrew פלס phalas, to roll, and so cover oneself in dust or ashes, which was practised in token of humiliation and grief, not only by the more eastern nations, see Job 42:6, but also by the Greeks and Trojans, as appears from Homer, Iliad xviii. l. 26; xxii. l. 414; xxiv. l. 640; compare Virgil, Aen. x. l. 844; and Ovid, Metam. lib. viii. l. 528. From the above Hebrew word, it is likely that the Saxon ful, the English foul, the Latin vilis, and the English vile, are derived. See Parkhurst under φαυλος.
Lest his deeds should be reproved - Or discovered. To manifest or discover, is one sense of the original word, ελεγχω, in the best Greek writers; and it is evidently its meaning in this place.

For every one that doth evil, hateth the light,.... Every man, the series of whose life and conversation is evil, hates Christ and his Gospel, cause they make manifest his evil deeds, convict him of them, and rebuke him for them:
neither cometh to the light; to hear Christ preach, or preached; to attend on the Gospel ministration and means of grace:
lest his deeds should be reproved; or discovered, and made manifest, and he be brought to shame, and laid under blame, and advised to part with them, which he cares not to do; see Ephesians 5:11.

reproved--by detection.