This verse is the centre of this passage (Revelation 9:1-12) and so its message needs to be underlined. The repetition serves to underline that message. The scorpion‑like locusts (demons) are not the central point (for the Bible is about God’s relation with people; angels, including the fallen, are “only” God’s servants sent to serve God’s people, see Hebrews 1:14). Rather, what the Lord does with people is central—in this passage specifically: how God responds to those people who defy him. Once past this emphasis on what is central in this paragraph, the attention turns again to the locusts who terrorize people so badly.
6 And in those days people will seek death and will not find it. They will long to die, but death will flee from them.