Genesis 3:24

"God placed cherubim and a flaming sword that moves"—this could be said in the one word movable—"to guard the way to the tree of life." Those who translate the Hebrew words in Scripture say that "cherubim" means in Latin "the fullness of knowledge." The flaming, movable sword means temporal punishments, because times move in their continual variety. It is called flaming because every tribulation burns somehow or other. But it is one thing to be burned until consumed, another to be burned until purified.

Throughout martyrdom Jesus is with you to show you the way to the paradise of God and how you may pass through the cherubim and the flaming sword that turns every way and guards the way to the tree of life. For both, even if they guard the way to pass through to the tree of life, guard it so that no one unworthy may turn that way to pass through to the tree of life. The flaming sword will hold fast those who have built upon the foundation that is laid, Jesus Christ, with wood, hay or straw, and the wood of denial, if I may call it that, which catches fire very easily and burns all the more. But the cherubim will receive those who by nature cannot be held by the flaming sword, because they have built with nothing that can catch fire. They will escort them to the tree of life and to all the trees God planted in the east and made to grow out of the ground.

At his departure from Paradise it says that God "caused a cherub and a sharp revolving sword to go round, to the east of the Garden of Eden, to protect the way to the Tree of Life.

Blessed is he who was pierced and so removed the sword from the entry to paradise.

Then, so that we may learn how great was the distance he moved him from the garden, Sacred Scripture teaches us this further fact in the words, "The Lord God drove Adam out and situated him opposite the garden of delight." [ Gen 3:24 ] Notice how each of the events proved an occasion of loving kindness on the part of the common Lord of all, and each example of punishment abounds with goodness. I mean, the expulsion was not the sole mark of love and goodness: there was also his location opposite the garden so that he might have unending anguish in recollecting from what heights he had fallen and cast himself into such depths. Yet even if the sight of it was the cause of unbearable pain, it was nevertheless an occasion of no little benefit: the constant sight proved to be an encouragement for this grieving man to carefulness in the future lest he fall into the same sin again. Such, after all, is the habit of human nature by and large: since, while we are in a position to enjoy good things, we don't know how to use them as we ought, we come to our senses with the loss of these things by learning through experience and gaining a sense of our own indifference. In this way we are taught by the change of fortunes from what heights we have fallen and with what troubles we have tortured ourselves. And so the instruction that the one who had lost his place there should dwell nearby and opposite the garden was a sign of deep concern in order that he might have the constant reminder from the sight of it and feel a sense of loss from it and never presume to eat from the tree through lusting after life while finding himself outside.