Revelation 9:13

“And the sixth angel sounded, etc.] His trumpet: and I heard a voice from the four horns of the golden altar, which is before God; the allusion is not to the altar of burnt offering, which was covered with brass, but to the altar of incense covered with gold; and hence here, and elsewhere, it is called “the golden altar”, and was a figure of the intercession of Christ; for on this altar incense was offered, which was typical of the prayers of the saints offered by Christ, through his mediation: the matter of this altar was shittim wood, a wood that is incorruptible, and of long duration, denoting the perpetuity of Christ's intercession; and its being covered with gold expresses the glory and…”

“a voice--literally, "one voice." from--Greek, "out of." the four horns--A, Vulgate (Amiatinus manuscript), Coptic, and Syriac omit "four." B and CYPRIAN support it. The four horns together gave forth their voice, not diverse, but one. God's revelation (for example, the Gospel), though in its aspects fourfold (four expressing world-wide extension: whence four is the number of the Evangelists), still has but one and the same voice. However, from the parallelism of this sixth trumpet to the fifth seal (Rev 6:9-10), the martyrs' cry for the avenging of their blood from the altar reaching its consummation under the sixth seal and sixth trumpet, I prefer understanding this cry from the four…”

“And the sixth angel sounded - See the notes on Revelation 8:2, Revelation 8:7. And I heard a voice from the four horns of the golden altar which is before God - In the language used here there is an allusion to the temple, but the scene is evidently laid in heaven. The temple in its arrangements was designed, undoubtedly, to be in important respects a symbol of heaven, and this idea constantly occurs in the Scriptures. Compare the Epistle to the Hebrews passim. The golden altar stood in the holy place, between the table of show-bread and the golden candlestick. See the notes on Hebrews 9:1-2. This altar, made of shittim or acacia wood, was ornamented at the four corners, and overlaid…”

“And the sixth angel sounded - Under this angel goes forth the second woe. And I heard a voice from the four corners of the golden altar - This golden altar is the heavenly pattern of the Levitical altar of incense. This voice signified that the execution of the wrath of God, mentioned Rev 9:20-21, should, at no intercession, be delayed any longer. Revelation 9:14”

“9:13-14 The four horns of the gold altar (see 8:3) are introduced with the sixth trumpet blast. Many excavations have uncovered altars with pointed horns at their four corners (see study note on Exod 27:2). • The voice carries the authority of God in the command to release the four angels. • These angels have been bound, suggesting their evil nature (cp. Rev 20:2; 1 Enoch 10; contrast Rev 7:1). Their location at the great Euphrates River probably refers to Assyria and Babylon, empires that had devastated the kingdoms of Israel and Judah and thus were symbols of destruction (see 2 Kgs 17:22-24; 25:1-11).”

“the sixth: Rev 9:1 a voice: Rev 8:3-5; Heb 9:24, Heb 10:21 Revelation 9:14”