Revelation 7:2,3 - Joseph Benson’s Commentary on the Old and New Testaments

And I saw another angel ascending from the east To intimate the progress which the gospel should make from the east to the west; having in his hand the seal of the living God In order to impress a mark upon those who should believe and obey the gospel, and dedicate themselves to his service. And he cried with a loud voice Thus showing the great importance of what he uttered; to the four angels to whom it was given At present to restrain the winds, but afterward to loose them with great violence, and by them to hurt the earth and the sea To injure them in a terrible manner; saying, Hurt not the earth, &c. Execute not your commission with respect to punishing the inhabitants of the earth; till we have sealed the servants of God Marked them out as such, and secured them from the impending calamities in a manner by which they shall be as clearly distinguished from the rest of mankind as if they were visibly marked on their foreheads. Bishop Newton thinks that this expression, sealing on the forehead, is used in allusion to the ancient custom of marking servants on their foreheads, to distinguish what they were, and to whom they belonged: and that as, among Christians, baptism was considered as the seal of the covenant between God and believers, so the sealing here spoken of signifies the admitting them into the visible church of Christ by baptism; and that their being said to be sealed on their foreheads can imply no less than that those who before, in times of persecution, had been compelled to worship God in private, should now make a free, open, and public profession of their religion, without any fear or danger of thereby exposing themselves to persecution. To this, however, must be added, that this sealing doubtless implies that very many should not only be baptized, and make a profession of Christianity, but should also be really converted to God, made new creatures in Christ; and, having believed in him, should, as the apostle observes, (Ephesians 1:13,) be sealed with the Holy Spirit of promise; that is, both stamped with God's image, and assured of their sonship by the Spirit of adoption and regeneration; and should possess that Spirit, in his witness and fruits, till they should receive the redemption of the purchased possession.