The lips of the righteous know what finds favor, but the mouth of the wicked only what is perverse.
NIV
The lips of the [uncompromisingly] righteous know [and therefore utter] what is acceptable, but the mouth of the wicked knows [and therefore speaks only] what is obstinately willful and contrary.
AMP
The lips of the righteous know what is acceptable: but the mouth of the wicked speaketh frowardness.
KJV