The material in the seven trumpets does not lend itself to a great deal of application to everyday life experience. But the following two points have been helpful to me.
1) How does the connection between the introduction to the trumpets (Rev. 8:3-5) and the fifth seal (Rev. 6:9-11) offer encouragement to those suffering for the sake of the gospel today? The martyrs’ cry for judgment in the fifth seal is answered by the seven trumpets (see Rev. 8:13). The trumpets are God’s judgment within history on powers that have been oppressing His people. The message of the trumpets is that God sees the suffering of His people and responds to the injustice, not only at the end of time, but in the course of history. Like Job, we may not always understand what God is doing, but we have reason to trust Him even in the darkest times.
2) The judgments of the first two trumpets fall on those powers that combined to crucify Jesus (the religious authorities of Jerusalem under Caiaphas and Roman civil authority under Pilate). What does this tell us about opposition to the gospel? Opposition to the gospel and those who embrace it tends to come from two distinct directions; opposition from inside the house and from outside the house. Jesus was crucified when the leaders of Israel (inside) combined with outside powers (Rome) to put Him to death. Historically, however, the greatest opposition to the true gospel and its followers often comes from those in the same faith.
A similar dynamic is seen in the parable of the prodigal son (Luke 15:11-32). The father is not only rejected (initially) by the son who left, but also by the one who stayed. The former is indifferent to the father, the latter is motivated by selfish gain. The prodigal son represents those today who care little about God and faith and are visibly on a different track. The elder son, on the other hand, represents those in the church who do not know or exhibit the character of the Father. On the outside they look pious and obedient, but inside is the heart of a rebel.