Yet he came not to judge or to enquire, but to pardon and remit transgressions, and to grant salvation through faith. How then fled they? Had He come and sat in His Judgment seat, what He said might have seemed reasonable; for he that is conscious to himself of evil deeds, is wont to fly his judge. But, on the contrary, they who have transgressed even run to one who is pardoning. If therefore He came to pardon, those would naturally most hasten to Him who were conscious to themselves of many transgressions; and indeed this was the case with many, for even publicans and sinners sat at meat with Jesus. What then is this which He saith? He saith this of those who choose always to remain in wickedness. He indeed came, that He might forgive men's former sins, and secure them against those to come; but since there are some so relaxed, so powerless for the toils of virtue, that they desire to abide by wickedness till their latest breath, and never cease from it, He speaks in this place reflecting upon these. "For since," He saith, "the profession of Christianity requires besides right doctrine a sound conversation also, they fear to come over to us, because they like not to show forth a righteous life. Him that lives in heathenism none would blame, because with gods such as he has, and with rites as foul and ridiculous as his gods, he shows forth actions that suit his doctrines; but those who belong to the True God, if they live a careless life, have all men to call them to account, and to accuse them. So greatly do even its enemies admire the truth." Observe, then, how exactly He layeth down what He saith. His expression is, not "He that hath done evil cometh not to the light," but "he that doeth it always, he that desireth always to roll himself in the mire of sin, he will not subject himself to My laws, but chooses to stay without, and to commit fornication without fear, and to do all other forbidden things. For if he comes to Me, he becomes manifest as a thief in the light, and therefore he avoids My dominion." For instance, even now one may hear many heathen say, "that they cannot come to our faith, because they cannot leave off drunkenness and fornication, and the like disorders."
Source: Homily on the Gospel of John 28