Question: where in the bible does it mention the seventh trumpet?
Answer: In the Book of Revelation, seven trumpets are sounded, one at a time, to cue apocalyptic events seen by John of Patmos (Revelation 1:9) in his vision (Revelation 1:1). The seven trumpets are sounded by seven angels and the events that follow are described in detail from Revelation Chapters 8 to 11.