Looking forward to the great tribulation (Matt. 24:21) What does the apostle John means with “‘Do not harm the earth or the sea or the trees, until after we have sealed the slaves of our God in their foreheads.’”—Rev. 7:1-3.
Paul Leonard of JWquestions-and_answers gives as reply: Some of the 144,000 are chosen but not yet sealed, or they have not all yet been chosen.
What is your opinion? Or your answer?
There are a number of figurative expressions found in the Bible. The book of Revelation probably uses the most. But to provide a basis for context regarding Re 7:2-4, first-century Christians are spoken of as being "sealed" by means of holy spirit, which is an advance token of their heavenly inheritance:
"But YOU also hoped in him after YOU heard the word of truth, the good news about YOUR salvation. By means of him also, after YOU believed, YOU were sealed with the promised holy spirit, which is a token in advance of our inheritance, for the purpose of releasing by a ransom [God's] own possession, to his glorious praise." (Eph 1:13, 14) NWT
The seal signifies their being God's possession and shows that they are truly in line for heavenly life:
"But he who guarantees that YOU and we belong to Christ and he who has anointed us is God. He has also put his seal upon us and has given us the token of what is to come, that is, the spirit, in our hearts." (2 Co 1:21, 22) NWT
Bearing a mark in the "forehead" is similarly used in a figurative way in the Bible to signify that one is a slave to the true God or to another:
"And as regards the glory of the God of Israel, it was taken up from over the cherubs over which it happened to be to the threshold of the house, and he began calling out to the man that was clothed with the linen, at whose hips there was the secretary's inkhorn. And Jehovah went on to say to him: "Pass through the midst of the city, through the midst of Jerusalem, and you must put a mark on the foreheads of the men that are sighing and groaning over all the detestable things that are being done in the midst of it."
"And to these [others] he said in my ears: "Pass through the city after him and strike. Let not your eye feel sorry, and do not feel any compassion. Old man, young man and virgin and little child and women YOU should kill off—to a ruination. But to any man upon whom there is the mark do not go near, and from my sanctuary YOU should start." So they started with the old men that were before the house." (Ezekiel 9:3-6) NWT