Cosmas Indicopleustes, on Gen 3:22

“And he said: Behold Adam is become as one of us, knowing good and evil: now, therefore, lest perhaps he put forth his hand, and take also of the tree of life, and eat, and live for ever.”

“Again, the two trees in the middle of Paradise mystically presignify the present state and the future, and the tree of the knowledge of good and evil is a type of this world which is mortal and mutable, having pleasures and pains, and being a school of discipline, just as Adam was taught by this tree both good and evil. Now the tree of life is a type of the future heavenly world, in which life and blessedness reign, for the saying: Lest he stretch forth his hand and take of the tree of life, signified the vast height of the tree and thereby signified the mansions above. As therefore He commanded the Cherubim with the flaming sword which turned every way, to guard the way to the tree of life, so He commanded the angels and the luminaries which revolve round the height of the firmament, to guard the way which is there that leads into the kingdom of heaven; intending to signify that the mansions above are meanwhile inaccessible to men. At His Passion therefore the Lord Christ carried with Him the soul of the thief into Paradise, having suspended the guardianship of the Cherubim and of the flaming sword, which turned every way. But after His resurrection, when He came to his ascension, He opened a passage through the host of the invisible Powers, and the luminaries and the firmament itself, and entered into the kingdom where immortality, and immutability, and blessedness reign. At the final consummation therefore, when the angels cease to make the luminaries revolve and when the stars fall, then the Cherubim and the flaming sword waving both ways no longer prevent men from entering into the true life, but the righteous, raised on high and traversing the new way and piercing the firmament with the Lord Christ, shall inherit the kingdom of life.”

Imported from an open dataset — not yet checked against the printed edition.