And he opened his MOUTH
This mouth is the one given to him in the previous verse
in BLASPHEMES AGAINST GOD,
This was the same accusation which lead to Christ's crucifixion (Matthew 9:3, Mark 14:53-65).
Jesus indicated that even blasphemy can be forgiven except for blasphemy against the Holy Spirit (Mark 3:28-30). Since the Holy Spirit is part of the triune God, the BLASPHEMY AGAINST GOD seals the "sea beast's" doom.
to BLASPHEME
His NAME encompasses all that is Christ from his humanness to the fulness of Deity (Colossians 2:8-15).
His TABERNACLE is the believer's place of worship. It is appropriate to identify the tabernacle as those who dwell in heaven (1 Corinthians 3:16), because believers have been removed from the earth in the GREAT UPTAKING.