The twenty-four elders who sat on their thrones before God prostrated themselves and worshiped God and said, "We give thanks to you, Lord God Almighty, who are and who were. For you have assumed your great power and have established your reign. The nations raged but your wrath has come, and the time for the dead to be judged, and to recompense your servants, the prophets, and the holy ones and those who fear your name, the small and great alike, and to destroy those who destroy the earth. Then God's temple in heaven was opened and the ark of his covenant could be seen in the temple. There were flashes of lightning, rumblings, and peals of thunder, an earthquake and a violent hailstorm.
The Book of Revelation is already a part of the New Testament but notice the similarity at the end passage with the incident at Mt Sinai where Moses met God, and the people were at the bottom of the mountain top. Flashes of lightning, earthquake and hailstorm. It is inherent that when God's presence is fully manifested, these phenomena could occur. Awe and reverence for God Almighty who deserves our praise!
This is an apocalyptic theme, with great hope for the future.