15:6 Out of the temple came the seven angels with the seven plagues. They were dressed in clean, shining linen and wore golden sashes around their chests.
Out of the temple came the seven ANGELS
Seven denotes completion; with the seven bowls these seven angels are going to carry, we will see the completion of God's wrath (verse 1).
This is the third set of seven angels. The first set were the angels to the seven churches (Revelation 2). The second set were the trumpet blowers (Revelation 8:6). This set has a different job to do as we will see.
with the seven PLAGUES.
While there is not a one to one correspondence to the plagues God sent via Moses upon Egypt, this indicates that PLAGUES are real and probably fall into categories:
Each category is a study unto itself.
They (the seven angels) were dressed in clean, shining linen and wore golden sashes around their chests.
This is really the Holy of Holies, "Ναός" in Greek, part of the temple. Thus these are angelic priest types. Compare to the earthly high priests (Exodus 28:28-30).
Linen denotes righteousness. It is this righteousness about which the song was sung (verse 3) and will be the garment of the bride, the believers, at the wedding supper (Revelation 19:8).
Compare how Daniel saw this Son of Man in his vision (Daniel 10:5-7).
Christ, as High Priest in heaven (Hebrews 5:1-10) is dressed this way (Revelation 1:13).
The sashes indicate service and a golden sash denotes GODLY SERVICE. Also, the sash had some protection value. Note what it is that these 7 angels will be assigned to do. They will be protected by God Himself.