Revelation 7:2,3

Revelation 7:2-3. The more peculiar contents of the vision follow. And I saw another angel ascending from the sunrising, from the quarter whence issues that great orb of day which is the symbol of the Sun of righteousness (comp. chap. Revelation 16:12). Having a seal of the living God, of that God who both has life and gives life.

And he cried with a great voice to the four angels already spoken of, telling them not to execute the judgments with which they were entrusted, till we shall have sealed the servants of our God on their foreheads. In Ezekiel 9:4, a man ‘clothed with linen and having a writer's inkhorn by his side' is instructed to go through the midst of Jerusalem, and to set ‘a mark upon the foreheads of the men that sigh and that cry for all the abominations that be done in the midst thereof.' That mark is for their security, and for a similar purpose the seal of this angel is applied. The sealed shall be kept safe in the times of trial that are to come. Their Redeemer will set them as a seal upon His heart and upon His arm (Song of Solomon 8:6), and no one shall pluck them out of His hand. For the opposite marking, the mark of the service of the Beast, see Revelation 13:17; Revelation 14:11. The Seer next beholds the number of the sealed.