20 For everyone practicing evil hates the light and does not come to the light, lest his deeds should be exposed.
Verse 20 stands in contrast to verse 21. In this verse we have “practicing evil” and in the next we have the contrast “does what is true.” Unbelievers not only love darkness but they “hate” the light.
20 For everyone practicing evil [worthlessness]
Those who reject the light have an even bigger problem—they “hate” the light. They hold no mere occasional value; they practice their belief system of hating the light as a course of life. The idea is they are living out a “worthlessness” value system.
It is important that “evil” does not refer to sin but to something worthless. It carries the idea of something paltry. Worthlessness is something of no account. It has very little use (Jn 5:29). Unbelievers have no ultimate meaning to their lives and no final goal.
hates the light
The apostle used the word “hates” 12 times in this gospel. Unbelief toward the Lord is no tepid affair but one of bitter resentment toward Him. The reason people hate Jesus is that coming to the light means they lose their value system.
People have a vested interest in not accepting Christ as their Savior.
Non-Christian hatred of the light is no tepid affair. Non-Christians have a deeply vested interest in not accepting the light of Jesus as truth. People who reject the light have a tendency to go deeper into spiritual perversity. They want to persevere in their belief system without changing anything. This makes them destitute for what God would have for them. They are deceived into thinking that their worthless values are indeed valuable. The reason for unbelief is not intellectual but volitional or moral.