Albert Barnes Commentary Revelation 19:6

"And I heard as it were the voice of a great multitude, and as the voice of many waters, and as the voice of mighty thunders, saying, Hallelujah: for the Lord our God, the Almighty, reigneth." — Revelation 19:6 (ASV)

And I heard as it were the voice of a great multitude. In Revelation 19:1, he says that he heard a great voice of much people; here he says he heard as it were a voice of great multitude.

That is, in the former case he heard a shout that he at once recognized as the voice of a great multitude of persons; here he says that he heard a sound not distinctly recognized at first as such, but which resembled such a shout of a multitude.

In the former case it was distinct; here it was confused—bearing a resemblance to the sound of roaring waters, or to muttering thunder, but less distinct than the former. This phrase would imply:

1. A louder sound; and
2. That the sound was more remote, and therefore less clear and distinct.

And as the voice of many waters. The comparison of the voices of a host of people with the roar of mighty waters is not uncommon in the Scriptures.

(See Barnes on Isaiah 17:12)

(See Barnes on Isaiah 17:13).

So in Homer—

"The monarch spoke, and straight a murmur rose,
Loud as the surges when the tempest blows;
That dashed on broken rocks tumultuous roar,
And foam and thunder on the stony shore."

And as the voice of mighty thunderings. The loud, deep, heavy voice of thunder. The distant shouts of a multitude may properly be represented by the sound of heavy thunder.

Saying, Alleluia. (See Barnes on Revelation 19:1).

This is the fourth time in which this is uttered as expressive of the joy of the heavenly hosts in view of the overthrow of the enemies of the church. The occasion will be worthy of this emphatic expression of joy.

For the Lord God omnipotent reigneth. Jehovah—God Almighty—the true God. The meaning is, that as the last enemy of the church is destroyed, he now truly reigns. This is the result of his power, and therefore it is proper that he should be praised as the omnipotent or Almighty God—for he has shown that he can overcome all his enemies, and bring the world to his feet.