Dates: c. 350 · Wikipedia
Summary: Cyril (c. 313–386), bishop of Jerusalem, gives the catechumens of his Catechetical Lectures the classic Eastern account of the descent: Christ "went down into the regions beneath the earth, that thence also He might redeem the righteous" — David, Samuel, the prophets, and John the Baptist, "imprisoned" since Adam — and "sent forth His prisoners out of the pit." The holding-place of the OT righteous is real, conscious, and emptied at the descent.
He went down into the regions beneath the earth, that thence also He might redeem the righteous. For, tell me, could thou wish the living only to enjoy His grace, and that, though most of them are unholy; and not wish those who from Adam had for a long while been imprisoned to have now gained their liberty? Esaias the Prophet proclaimed with loud voice so many things concerning Him; would you not wish that the King should go down and redeem His herald? David was there, and Samuel, and all the Prophets, John himself also … Would you not wish that He should descend and redeem such as these?
— Catechetical Lecture 4, §11–12, newadvent.org. Cyril treats the descent as the redemption of a named company of the righteous dead — the patriarchs, prophets, and the Baptist — who had been "imprisoned" in the underworld "from Adam" and are now set free. The intermediate state of the OT saints is a genuine detention that only Christ's descent ends.
The Sun was darkened, because of the Sun of Righteousness [Malachi 4:2]. Rocks were rent, because of the spiritual Rock. Tombs were opened, and the dead arose, because of Him who was free among the dead; He sent forth His prisoners out of the pit wherein is no water [Zechariah 9:11].
— Catechetical Lecture 13, §33–34, newadvent.org. Cyril reads Zechariah 9:11 ("the pit wherein is no water") of Hades and applies it to the crucifixion's aftermath: Christ, "free among the dead," releases the captives. The descent is the moment the prison of the righteous is opened.
The tree brought ruin to Adam. It will bring you into paradise. Do not fear the Serpent. He will not throw you out, for he has fallen from heaven. I do not say to you, "This day you will depart," but "This day you will be with me." Take heart; you will not be thrown out. Do not fear the flaming sword, because it stands in awe of its Lord.
— Catechetical Lecture 13, §31, newadvent.org. Like Origen, Cyril sets Luke 23:43 against Eden: the cross undoes the tree's ruin, the "flaming sword" that guarded paradise yields to its Lord, and the thief enters paradise "this day" — a conscious, immediate entry, granted by the descending Christ.
Death was struck with dismay on beholding a new visitant descend into Hades, not bound by the chains of that place. Wherefore, O porters of Hades, were ye scared at sight of Him? … The holy prophets ran unto Him, and Moses the Lawgiver, and Abraham, and Isaac, and Jacob; David also, and Samuel, and Esaias, and John the Baptist, who bore witness when he asked, Art Thou He that should come, or look we for another? All the Just were ransomed, whom death had swallowed; for it behoved the King whom they had proclaimed, to become the redeemer of His noble heralds. Then each of the Just said, O death, where is thy victory? O grave, where is thy sting? For the Conqueror hath redeemed us.
— Catechetical Lecture 14, §19, newadvent.org. Cyril's most dramatic statement of the descent: the crucified Christ enters Hades "not bound by the chains of that place," its "porters" recoil in terror, and the whole company of the OT just — patriarchs, lawgiver, prophets, and the Baptist — "ran unto Him" and were "ransomed … whom death had swallowed." The descent is a liberation, the King redeeming "His noble heralds," and the victory-cry of 1 Corinthians 15:55 ("O death, where is thy victory?") is put in the mouths of the freed righteous.