Why is God not unjust during the tribulation according to Revelation 15?
The judgments poured out during the tribulation are exactly what they deserve, so God is not unjust. The song of Moses and the Lamb declares His works great and marvelous, His ways just and true, and His judgments made manifest.
Les explains that no matter how awful the tribulation experiences are, God isn't being unfair or unjust; they are getting exactly what they deserved. The song of Moses and the Lamb declares God's works are great and marvelous, His ways just and true, and He alone is holy. John then sees the temple opened and seven angels with seven plagues, and seven golden bowls full of the wrath of God, a symbolic picture of how that wrath will be poured out.