Revelation 16:7

And I heard a voice from the altar, saying, Yes, O Lord God Almighty, true and righteous are thy judgments.

Revelation 6:9

And when he opened the fifth sea, I saw, under the altar, the souls of those who were slaughtered on account of the word of God, and the testimony which they held.

Revelation 19:2

for his judgments are true and righteous; for he has judged the great harlot, who corrupted the earth with her fornication; and he has avenged the blood of his servants shed by her hand.

Revelation 14:18

And another angel came from the altar, having power over the fire; and he cried out with a loud cry to him who had the sharp sickle, saying, Put forth your sharp sickle, and lop off the clusters of the vine upon the earth; for its grapes are ripe.

Revelation 8:3-5

And another angel came, and stood before the altar, having a golden censer; and there was given to him much incense, that he might present it with the prayers of all the saints, upon the golden altar which was before the throne.

Revelation 13:10

If any one lead them into captivity, he shall be led into captivity: if any one slay with the sword, he shall himself be slain with the sword. Here is the patience and the faith of the saints.

Revelation 14:10

he also shall drink of the wine of the indignation of God, which is tempered, without mixture, in the cup of his wrath; and he shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb.

Revelation 15:3-4

And they sang the song of Moses, the servant of God, and the song of the Lamb; saying, Great and wonderful are thy works, O Lord God Almighty; righteous and true are thy ways, O King of Saints.

Treasury of Scripture Knowledge

Summary

And I heard another out of the altar say, Even so, Lord God Almighty, true and righteous are thy judgments.

Bible References

Out

Revelation 6:9
And when he opened the fifth sea, I saw, under the altar, the souls of those who were slaughtered on account of the word of God, and the testimony which they held.
Revelation 8:3
And another angel came, and stood before the altar, having a golden censer; and there was given to him much incense, that he might present it with the prayers of all the saints, upon the golden altar which was before the throne.
Revelation 14:18
And another angel came from the altar, having power over the fire; and he cried out with a loud cry to him who had the sharp sickle, saying, Put forth your sharp sickle, and lop off the clusters of the vine upon the earth; for its grapes are ripe.

Even

Revelation 15:3
And they sang the song of Moses, the servant of God, and the song of the Lamb; saying, Great and wonderful are thy works, O Lord God Almighty; righteous and true are thy ways, O King of Saints.

True

Revelation 13:10
If any one lead them into captivity, he shall be led into captivity: if any one slay with the sword, he shall himself be slain with the sword. Here is the patience and the faith of the saints.
Revelation 14:10
he also shall drink of the wine of the indignation of God, which is tempered, without mixture, in the cup of his wrath; and he shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb.
Revelation 19:2
for his judgments are true and righteous; for he has judged the great harlot, who corrupted the earth with her fornication; and he has avenged the blood of his servants shed by her hand.