'Evil' in the Bible

Watch out, brothers, lest there be in some of you an evil, unbelieving heart, [with the result that you] fall away from the living God.

But solid food is for the mature, who because of practice have trained their faculties for the distinguishing of both good and evil.

let us approach with a true heart in the full assurance of faith, our hearts sprinkled [clean] from an evil conscience and our bodies washed with pure water.