Each of previous “sevens” had an introductory paragraph setting the stage for what was to occur in the “seven.” Revelation 15:1–8 contains the material introducing the seven bowls of God’s wrath poured out in Revelation 16:1–21. As in previous introductions, the material of Revelation 15:1–8 provides the context and sets the tone for the details of Revelation 16.
1 Then I saw another sign in heaven, great and amazing, seven angels with seven plagues, which are the last, for with them the wrath of God is finished.