Revelation 6:9

6:9 Now when the Lamb opened the fifth seal, I saw under the altar the souls of those who had been violently killed because of the word of God and because of the testimony they had given.

Revelation 9:13

9:13 Then the sixth angel blew his trumpet, and I heard a single voice coming from the horns on the golden altar that is before God,

Exodus 37:25-26

The Making of the Altar of Incense

37:25 He made the incense altar of acacia wood. Its length was a foot and a half and its width a foot and a half – a square – and its height was three feet. Its horns were of one piece with it. 37:26 He overlaid it with pure gold – its top, its four walls, and its horns – and he made a surrounding border of gold for it.

Exodus 40:26

40:26 And he put the gold altar in the tent of meeting in front of the curtain,