Charles Ellicott Commentary Titus 1:16

"They profess that they know God; but by their works they deny him, being abominable, and disobedient, and unto every good work reprobate." — Titus 1:16 (ASV)

They profess that they know God; but in works they deny him.—These bitter enemies of the truth, Titus must remember, will present themselves under the guise of friends. They will openly align themselves with the Christian community, confessing God with their lips, but in their way of life, in their acts, practically denying the very things they were so careful to affirm with their lips; in other words, retracting, withdrawing, the solemn declaration of faith they had been making.

Being abominable.—This is the only place where this strong expression is used in the New Testament. It signifies that the life and actions of these men, who professed to be His servants, had made them hateful in the sight of God.

And disobedient.—Rebellious and opposed to all law and order would Titus find them.

And unto every good work reprobate.—As a consequence of their hypocritical, selfish, and defiled life, these men, whenever any good and noble work needed to be done, were simply useless and worthless. And to teachers of this kind were many of the Cretan believers content to go for instruction in Christian doctrine and practice.