Titus 1:15, 16

To the pure [in heart and conscience] all things are pure, but to the defiled and corrupt and unbelieving nothing is pure; their very minds and consciences are defiled and polluted. They profess to know God [to recognize, perceive, and be acquainted with Him], but deny and disown and renounce Him by what they do; they are detestable and loathsome, unbelieving and disobedient and disloyal and rebellious, and [they are] unfit and worthless for good work (deed or enterprise) of any kind. (Titus 1:15, 16 AMP)