'Thunders' in the Bible

he shouted in a loud voice as a lion roars. When he shouted, the seven thunders spoke with voices of their own.

When the seven thunders spoke, I was going to write, but I heard a voice from heaven say, "Seal up what the seven thunders have said, and don't write it down."

Then the seven thunders told me, "You must prophesy again about many nations, nations, languages, and kings."