1 After this I saw four angels standing at the four corners of the earth, restraining the four winds of the earth so that no wind could blow on the earth or on the sea or on any tree.
Who are these four angles? In Revelation 9:15 there are also four angels that are unleashed with one of the Trumpets and are clearly demons who come to make war. The context here doesn’t say but it does make a distinction between the angel who has the seal, see verse 2, or the mark of God with the four angels who do not have the seal of God. The four angels could possibly be fallen angels since they like those in Revelation 9:15 will bring destruction upon the earth. Another possibility that they (the four angels) could be demons is because God is going to protect His children from these angels. Only demons attack believers, not angels from the Lord, see Job 1.
Angels from the Lord and fallen angels are participating in God’s judgments, see Revelation 9:1-12 (demons) & see Revelation 16:8 (an angel from the Lord)
The phrase “four corners of the earth” could refer to that there will be no escaping what’s coming.
The four angels were holding back God’s judgments that not even the wind was allowed to blow on the earth until the 144,000 were sealed with God’s seal, see verse 3.
2 Then I saw another angel, who had the seal of the living God rise up from the east. He cried out in a loud voice to the four angels who were empowered to harm the earth and the sea:
The phrase “who had the seal of the living God” means a distinguishable mark to reveal that the angel belongs to the Lord. Satan through the Antichrist will mark those who belong to them.
3 “Don’t harm the earth or the sea or the trees until we seal the slaves of our God on their foreheads.”
God protects His saints by sealing them with His mark (Jesus and the Father’s name was placed on their foreheads, see Revelation 14) so that they will be off-limits to the four angels.
4 And I heard the number of those who were sealed: 144,000 sealed from every tribe of the Israelites:
The ones who are being sealed are messianic Jews who came to believe that Jesus is the Messiah through faith.
5 12,000 sealed from the tribe of Judah,
12,000 from the tribe of Reuben,
12,000 from the tribe of Gad,
6 12,000 from the tribe of Asher,
12,000 from the tribe of Naphtali,
12,000 from the tribe of Manasseh,
7 12,000 from the tribe of Simeon,
12,000 from the tribe of Levi,
12,000 from the tribe of Issachar,
8 12,000 from the tribe of Zebulun,
12,000 from the tribe of Joseph,
12,000 sealed from the tribe of Benjamin.
These 12,000 per tribe are selected for a special ministry for the Lord because they were blameless and righteous before God’s eyes, see Revelation 14:5 and He will protect them so that they may accomplish His will.
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Spiritual Minefield 
I wonder if fallen angels still wear white? I would think when they decided to rebel against God, they probably decided to change outfits too to something more sinister and fitting their true nature of darkness.
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Yes, demons when going out to deceive put on their white uniforms.
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Oh yeah. Good point. The reference to the angel of light completely escaped me. It’s not deception if it’s obvious.
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Exactly
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