Revelation 7:3

³ Saying, Harm neither the earth nor the sea nor the trees, until we have sealed the bond servants of our God upon their foreheads.

• This verse shows us that there is going to be great salvation during the end times. Our Father will seal people from every nation, tongue, and tribe. His Spirit will be poured out on all mankind, just as God had Joel prophesy.  
• Tree’s represent nations.
• Sea represents groups of people, metropolitan areas.
• Earth represents less populated groups or areas. So no part of the world can be harmed until the Bride of Christ is fully empowered to serve during the last days.
• And do not grieve the Holy Spirit of God [do not offend or vex or sadden Him], by Whom you were sealed (marked, branded as God's own, secured) for the day of redemption (of final deliverance through Christ from evil and the consequences of sin). Ephesians 4:30  
• The term forehead is used a lot in the Book of Revelation. In prophesy, “forehead,” is used to show our innermost thoughts, our minds, our beings. When I think of a forehead, I think of how they are plain to see, they are right out there in front of everyone. So it will be plain to see who is of God and who is not of Him during the final three and a half years of this world. Who and what we are, will be so plain to see during the last days, because it will be the Holy Spirit within us, the Fire in our belly’s, that makes us it so plain to see. Right now, it’s not so plain to see who is of God and who isn’t. Now we have to test the spirits, just as 1 John 4:1 teaches us to. But during the Great Tribulation, it will be plain to see who is the Bride of Christ and who isn’t! The luke warm will be cast out, there will only be hot and cold at this time in history! 
• We are a body, one heart, one mind, and one accord. There are not several bodies; there is only one body of Christ! Notice that the angel does not proclaim that we must be raptured or rescued, but sealed. Our Father’s wrath does not extend into the inhabitants of Heaven, so why would we need sealed if we were there? However we would absolutely need sealed if we are still on the earth. Also, for those who believe that the Holy Spirit is removed from the earth during the great Tribulation, I would like to ask this, who is doing the sealing? Ephesians 4:30