Titus 1:13-15

13 This witness is true; for which cause convict them sharply, so that they may be sound in the faith,

14 not giving heed to Jewish myths and commandments of men, turning away from the truth.

15 To the pure all things [are] pure. But to those who are defiled and unbelieving nothing [is] pure, but even their mind and conscience is defiled.