Cyclopedia of Biblical, Theological and Ecclesiastical Literature
(μνεύματα ἀκάθαρτα ), a frequent term in Scripture for unholy angels (Matthew 10:1, etc.). See the Christian Remembrancer, July, 1862. (See DAEMON).
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McClintock, John. Strong, James. Entry for 'Spirits, Unclean'. Cyclopedia of Biblical, Theological and Ecclesiastical Literature. https://www.studylight.org/encyclopedias/eng/tce/s/spirits-unclean.html. Harper & Brothers. New York. 1870.