"You want to capture the mood of the original song if you can, of course," he said. "This is a very special song — a very, very ancient song, and I always found this song to have multiple layers of meaning because it's ... actually called an advent song." Cooper continued, "It's known as an Advent song that is singing for the first Advent of Jesus, the incarnation, the Savior, to come into the world, to take away the sin of the world." He noted, though, that many people sing "O Come, O Come, Emmanuel" in desperation for Christ's Second Coming. Seeing so much pain and suffering in the world, they long for the Lord to come back.

"The world is not going good," he said. "This is bad, and we are we're in a certain amount of suffering here and we are eagerly expecting the coming, the return of the King, if you will, the return of the Savior." Cooper said this is just one of the layers to the song and that Skillet wanted to capture the original intent as well as this somberness. Thus, the first half of the song is lighter and the second is a bit heavier. "The second half, we said, we got to go hard," he said. "We got to go Skillet on this thing." Known for their rock chops, the band infused some of that into the mix — and their fans have thus far loved the song. But rather than get loud without purpose, Cooper said there was a reason behind it.

"You're expressing the hardship of the world we live in," he said. "The fact that our loved ones are going to die or that maybe this year you've had to live with ... a death in the family, watching your parent die, watching your kid die, whatever it may be. These absolute heartaches that we are eagerly waiting for all of the old to be made new." Mixing these themes with the power of God coming into the world, Cooper said it's important to show, through music, the deeper meaning of both the First and Second Comings of Christ.

"He defeats the devil," Cooper said. "He defeats the demons. He defeats the power of sin." The singer said they felt the song could, thus, capture these spiritual realities in a "very loud, triumphant, Earth-shaking way." Cooper said he was shocked by some of the reactions. Watch for more.