Titus 1:13-16

13This testimony is true. For which cause reprove them sharply, that they may be sound in the faith, 14not giving heed to Jewish fables, and commandments of men who turn away from the truth. 15To the pure all things are pure: but to them that are defiled and unbelieving nothing is pure; but both their mind and their conscience are defiled. 16They profess that they know God; but by their works they deny him, being abominable, and disobedient, and unto every good work reprobate.