I saw in heaven another great and marvelous sign: seven angels with the seven last plagues—last, because with them God’s wrath is completed.
This passage marks the beginning of the seven final plagues, and judgment, on the world (Lev. 26:21). The wrath is complete. This is judgment on those who will not accept God.
2 And I saw what looked like a sea of glass glowing with fire and, standing beside the sea, those who had been victorious over the beast and its image and over the number of its name. They held harps given them by God
First we see a sea of glass that is glowing with first (judgment). These who have been victorious over the beast are the true faithful and are presented with harps. This is no doubt where we get the image of angels floating on clouds playing harps. But The real victory isn’t to simply preserve their own lives, but to stand firm, against immense evil, possibly even losing their life in the process, to stand before God as a faithful servant (Matthew 25:23) They would not give allegiance to the beast, worship him or receive his mark.
3 and sang the song of God’s servant Moses and of the Lamb: “Great and marvelous are your deeds, Lord God Almighty. Just and true are your ways, King of the nations. 4 Who will not fear you, Lord, and bring glory to your name? For you alone are holy. All nations will come and worship before you, for your righteous acts have been revealed.”
The song of Moses and the Lamb is all about how God works, His ways, His worthiness and worship. This is the union of the Law and Love.
5 After this I looked, and I saw in heaven the temple—that is, the tabernacle of the covenant law—and it was opened. 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.
The 7 angels come out of the tabernacle and they are carrying 7 plagues. The way they are dressed reminds us of purity. They bring God’s judgment.
7 Then one of the four living creatures gave to the seven angels seven golden bowls filled with the wrath of God, who lives for ever and ever. 8 And the temple was filled with smoke from the glory of God and from his power, and no one could enter the temple until the seven plagues of the seven angels were completed.
These are the bowls of judgment. The judgment is irreversible. No one can enter the temple until the plagues are completed. This is the end of God’s patience. God is no longer waiting for humankind to come to repentance. This is the punishment for the rejection of his offer of salvation through Jesus Christ. (2 Peter 3:9-11).