Revelation 16:7

And I heard one speaking from the altar, Yes, Lord God Almighty, true and righteous are thy judgments.

Revelation 6:9

And when he opened the fifth seal, I saw beneath the altar the souls of those who had been slain on account of the word of God, and the testimony which they had.

Revelation 19:2

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

Revelation 14:18

and another angel came out from the altar, having power over the fire; and he called with a great voice to the one having the sharp sickle, Send in thy sharp sickle, and reap the clusters of the vintage of the earth; because her grapes are fully ripe.

Revelation 8:3-5

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

Revelation 13:10

If any one leads into captivity he goes into captivity: if any one kills with a sword, it behooves him to be killed with a sword. Here is the patience and the faith of the saints.

Revelation 14:10

and he shall drink of the wine of the wrath of God, having been poured out without mixture in the cup of his indignation; 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 are singing the song of Moses the servant of God, and the song of the Lamb, saying, Great and wonderful are thy works, O Lord God Omnipotent; true and righteous are thy ways, thou King of the nations:

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 seal, I saw beneath the altar the souls of those who had been slain on account of the word of God, and the testimony which they had.
Revelation 8:3
And another angel came and stood before the altar, having a golden censer; and much incense was given to him, that he shall offer with the prayers of all saints upon the golden altar which is before the throne.
Revelation 14:18
and another angel came out from the altar, having power over the fire; and he called with a great voice to the one having the sharp sickle, Send in thy sharp sickle, and reap the clusters of the vintage of the earth; because her grapes are fully ripe.

Even

Revelation 15:3
And they are singing the song of Moses the servant of God, and the song of the Lamb, saying, Great and wonderful are thy works, O Lord God Omnipotent; true and righteous are thy ways, thou King of the nations:

True

Revelation 13:10
If any one leads into captivity he goes into captivity: if any one kills with a sword, it behooves him to be killed with a sword. Here is the patience and the faith of the saints.
Revelation 14:10
and he shall drink of the wine of the wrath of God, having been poured out without mixture in the cup of his indignation; 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
because his judgments are true and righteous; because he has judged the great harlot, who corrupted the earth by her fornication, and he has avenged the blood of his servants from her hand.