And the sixth angel sounded, and I heard a voice from the four horns of the golden altar which is before God, The four horns of the golden altar - This is another not very obscure indication that the Jewish temple was yet standing.
Related Commentaries of Revelation 9:13
Revelation 9:13
13 And the sixth angel sounded, and I heard a voice from the four horns of the golden altar which is before God,