The voice came from the temple. The temple of heaven was the prototype of the tabernacle Moses built (Exodus 25:40; Hebrews 8:5). The holy inhabitant of the tabernacle was God himself, enthroned in the Most Holy Place (Exodus 25:22; Numbers 7:89; Psalm 99:1). That reality directs us to understand that the loud voice John hears from the temple is the voice of God himself.

Furthermore, as the voice instructs angels what to do and as angels are God’s servants (see Psalm 103:20–21; Hebrews 1:14), it again follows that the voice John hears needs to be the voice of God himself. Added to that, we also need to consider the previous verse, Revelation 15:8, where we learned that the glory of God filled the sanctuary, which is the same word translated in Revelation 16:1 as temple from where the voice came. Finally, in Revelation 16:17 we read the identical line about a loud voice coming from the temple, this time with the addition of from the throne. In light of Revelation 4:2, that is necessarily God’s throne. These factors all direct us to conclude that the voice John heard was the voice of God himself.