Revelation 9:13

Then the sixth angel sounded [his trumpet], and I heard a solitary voice from the four horns of the golden altar which stands before God,

Exodus 30:2-3

It shall be a cubit long and a cubit wide. It shall be square and it shall be two cubits high. Its horns of one piece with it.

Hebrews 9:24

For Christ did not enter into a holy place made with hands, a mere copy of the true one, but [He entered] into heaven itself, now to appear in the very presence of God on our behalf;

Hebrews 10:21

and since we have a great and wonderful Priest [Who rules] over the house of God,

Revelation 8:3-5

Another angel came and stood at the altar. He had a golden censer, and much incense was given to him, so that he might add it to the prayers of all the saints (God’s people) on the golden altar in front of the throne.

Revelation 9:1

Then the fifth angel sounded [his trumpet], and I saw a star (angelic being) that had fallen from heaven to the earth; and the key of the bottomless pit (abyss) was given to him (the star-angel).

Treasury of Scripture Knowledge

Summary

And the sixth angel sounded, and I heard a voice from the four horns of the golden altar which is before God,

The sixth

Bible References

The sixth

Revelation 9:1
Then the fifth angel sounded [his trumpet], and I saw a star (angelic being) that had fallen from heaven to the earth; and the key of the bottomless pit (abyss) was given to him (the star-angel).

A voice

Revelation 8:3
Another angel came and stood at the altar. He had a golden censer, and much incense was given to him, so that he might add it to the prayers of all the saints (God’s people) on the golden altar in front of the throne.
Hebrews 9:24
For Christ did not enter into a holy place made with hands, a mere copy of the true one, but [He entered] into heaven itself, now to appear in the very presence of God on our behalf;
Hebrews 10:21
and since we have a great and wonderful Priest [Who rules] over the house of God,