And 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
In many love of sin rather than any boasted self-righteousness keeps them from the Savior. They do not believe in Jesus, not because they have any doubt about the truths of Christianity, but because they have an enslaving love for their favorite sin.
“Why,” says one, “if I were to believe in Christ, of course, I must obey Him—to trust and to obey go together. Then I could not be the drunkard I am, I could not trade as I do, I could not practice secret licentiousness, I could not frequent the haunts of the ungodly, where laughter is occasioned by sin and mirth by blasphemy. I cannot give up these my darling sins.” Perhaps this sinner hopes that one day, when he cannot any longer enjoy his sin, he will meanly sneak out of it and try to cheat the devil of his soul. But meanwhile he prefers the pleasures of sin to obedience to God, and unbelief to acceptance of his salvation.
O sweet sin! O bitter sin! How are you murdering the souls of men! As certain serpents before they strike their prey fix their eyes upon it and fascinate it, and then at last devour it, so does sin fascinate the foolish sons of Adam. They are charmed with it and perish for it. It yields but a momentary joy, and the wage thereof is eternal misery, yet are men enamored of it. The ways of the strange woman and the paths of uncleanness lead most plainly to the chambers of death yet are men attracted thereto as moths to the blaze of the candle, and so are they destroyed…The preference of a lust to God is a greater insult still. To obey our passions rather than His will, and to prefer sin to His mercy, this is the crime of crimes. May God deliver us from it, for His mercy’s sake. ~ C.H. Spurgeon
https://www.blueletterbible.org/comm/spurgeon_charles/sermons/1012.cfm