After these things.

Here we have a stark contrast to the previous chapter.

While the great Babylon is being judged by God on earth and suffering tits just punishment, the Church in Heaven, (represented by the twenty-four elders) and those who made it through the Great Tribulation by overcoming their challenges (the antichrist in particular), all burst into joy and happiness at the sight of God’s justice prevailing over those who had opposed the Creator.

The four times that word “hallelujah” is spoken, reflects the exultant joy of those watching God’s judgments being done.