Jamieson, Fausset and Brown on Revelation 13:6

6. opened ... mouth--The usual formula in the case of a set speech, or series of speeches. Re 13:6, 7 expand Re 13:5.

blasphemy--So B and Andreas. A and C read "blasphemies."

and them--So Vulgate, Coptic, Andreas, and Primasius read. A and C omit "and": "them that dwell (literally, 'tabernacle') in heaven," mean not only angels and the departed souls of the righteous, but believers on earth who have their citizenship in heaven, and whose true life is hidden from the Antichristian persecutor in the secret of God's tabernacle. See on Re 12:12; Joh 3:7.