The fourth angel poured his bowl on the sun, and it was allowed to scorch men with fire; men were scorched by the fierce heat, and they cursed the name of G_d who had power over these plagues, and they did not repent and give him glory.
The fifth angel poured his bowl on the throne of the beast, and its kingdom was in darkness; men gnawed their tongues in anguish and cursed the G_d of heaven for their pain and sores, and they did not repent of their deeds.
cf. CCC 979 In this battle against our inclination towards evil, who could be brave and watchful enough to escape every wound of sin? “If the Church has the power to forgive sins, then Baptism cannot be her only means of using the keys of the Kingdom of heaven received from Jesus Christ. The Church must be able to forgive all penitents their offenses, even if they should sin until the last moment of their lives.”
 Rv 16:8-9
 Rv 16:10-11