"After this I saw four angels standing at the four corners of the earth, holding back the four winds of the earth, that no wind might blow on earth or sea or against any tree. 2 Then I saw another angel ascending from the rising of the sun, with the seal of the living God, and he called with a loud voice to the four angels who had been given power to harm earth and sea, 3 saying, “Do not harm the earth or the sea or the trees, until we have sealed the servants of our God on their foreheads.”"
Revelation 7:1-3
The seventh seal does not, as one might expect it to do, follow immediately after the sixth. There is a pause in the progress of the vision, and for a whole chapter we are given to see the angels of God at work in human history. 'After these things' in 1 does not mean in relation to time, but to a fresh aspect of truth, and a new comprehension of it. The judgments mentioned in chapter 6 under the first six seals are now comprehended as winds held by four angels standing on the four corners of the earth. The reason why there is delay before the final seal is broken (which seal, as we shall see in chapter 8, opens into the seven trumpet judgments) is that something must first be accomplished, namely, the sealing of the 144,000. God's own are sealed against the trials and tribulations, that is, they are kept from falling and protected amid the judgments falling around them. We may recall the words of Psalm 91:7, 'A thousand shall fall at thy side, and ten thousand at thy right hand; but it shall not come nigh thee'. Sealed by the Holy Spirit, they are kept, amid all the temptations and trials of life, till He comes. On any interpretation (and there is wide difference on this point), it is very wonderful to realise that God will surely fill up the roll of His elect before Christ takes His power and reigns. None whom He has predestinated to eternal life will be missing, and the final reckoning is delayed until every last one is gathered out, sealed and welcomed into the Father's house.