Andreas of Caesarea — on Rev 7:2-3 (COMMENTARY ON THE APOCALYPSE 7:2-3)

“This was revealed long ago to Ezekiel concerning him who was clothed in a fine linen robe and who sealed the foreheads of those who mourned so that the righteous would not be destroyed along with the wicked, since the virtue of the saints is hidden and is unknown even to the angels. This is shown also here to the blessed [John], that a preeminent holy power encourages the avenging holy angels to do nothing until they might recognize the servants of the truth by virtue of their having been sealed. Although this has happened partially long ago when those who believed in Christ fled from the siege of Jerusalem by the Romans into very many destinations, the great James having showed to blessed Paul their great number, then, as has been said, this will especially occur at the coming of the antichrist when the seal of the life-giving cross will separate from the faithless the faithful who bear without shame and with boldness the sign of Christ before the impious. Therefore, the angel says, "Do not harm the earth of the sea or the trees, until we have sealed the servants of our God upon their foreheads." Just as the creation, created for our sakes, shares in the torments with us who are being chastised, so too it will be made clean with the saints who are being glorified. Through these words we learn that the virtuous will require the power of angelic assistance before the arrival of the trials which come because of the seal of the Spirit which is given to us. [We learn further] that this seal will reveal its power to that extent that we add our own work to it, for everything remains without aid which by its own will wills not to be aided.”