Oecumenius — on Rev 3:7 (Commentary on Revelation)

“To those in Philadelphia, it says, write: These things says the Holy one, the True one. The Holy one is indeed the Son of God. Then this is also testified by the Seraphim, who unite a threefold "holy" into one lordship, having nothing earthly or sinful, even though the Word became flesh. "For he committed no sin. Nor was deceit found in his mouth," according to the voice of the prophet Isaiah. (Isa. 53:9) And it is true that it is also said, the True one; and He also is called God, and the title is not false. For God is truly Emmanuel, even if the accursed Nestorius does not wish this; He became man without ceasing to be God, and He is truly man, even if the God-hated Eutyches finds this difficult. Which is truly the case, and nothing but a matter of fact, not as the Nestorians claim by way of allegory, nor as the Eutychians assert by opinion or imagination, nor the accursed and detestable race of the Manichaeans. He says He who holds the key of David. To hold the key means to hold authority. For the one entrusted with the key of the house is given the authority to open and to shut. And this is clearly demonstrated in the Gospels in the promises made to Peter. "For I will give you the keys of the kingdom of heaven; and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven." (Matt. 16:19) Since therefore the key signifies authority, the one who holds the key of David clearly indicates that just as David reigned over the physical Israel, so too I reign over both the physical and the spiritual Israel, although the nature of the authority is exchanged with incomparable superiority. For what equality is there between man and God? This was also proclaimed by the divine angel Gabriel to the virgin concerning the Lord, saying, "And the Lord God will give him the throne of David his father; and he shall reign over the house of David forever, and of his kingdom there shall be no end." (Luke 1:32-33) Since Christ founded a likeness to the kingdom of David, it is fittingly said by the one who holds the key of David. Then, having remained firm in the manner of the key, He brings it forward: He who opens and no one will shut; and He who shuts, and no one opens. For if God is the one who justifies; who is the one who condemns? If God is the one who condemns; who is the one who justifies? For He says to open and to shut, means to justify and to condemn.”