Oecumenius — on Rev 7:2 (Commentary on Revelation)

“"Then I saw another angel ascending from the east, having the seal of the living God, and he cried out with a loud voice to the four angels to whom it was granted to harm the earth and the sea, saying, 'Do not harm the earth or the sea or the trees until the servants of our God have been sealed.'" The divine angel is said to come from the east, where the sun rises, but not from the west or the evening, symbolizing announcing of the Gospel and promises of blessings.”