Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
That faculty of the mind, or inborn sense of right and wrong, by which we judge of the moral character of human conduct. It is common to all men. Like all our other faculties, it has been perverted by the Fall (Jn. 16:2; Acts 26:9; Rom. 2:15). It is spoken of as "defiled" (Tit. 1:15), and "seared" (1 Tim. 4:2). A "conscience void of offence" is to be sought and cultivated (Acts 24:16; Rom. 9:1; 2 Cor. 1:12; 1 Tim. 1:5, 19; 1 Pet. 3:21).