Lactantius, Divine Institutes 7.12

Let us now refute the arguments of those who argue against us, arguments that Lucretius set out in his third book. He says that since the soul is born with the body, it must necessarily perish with the body. But the reasoning for the two is not equal. The body is solid and tangible, perceived by both eyes and hand, while the soul is subtle and eludes both touch and sight. The body is fashioned and solidified from the earth; the soul has nothing concrete in itself, no earthly weight, as Plato used to say. For it could not possess such great skill, such great power, such great swiftness unless it drew its origin from heaven. Therefore, because the body is formed from a heavy and corruptible element, it is tangible and visible; it decays and dies and cannot repel force, since it falls under both sight and touch. But the soul, because by its subtlety it flees all touch, cannot be dissolved by any blow. Thus, although they are born connected and united, and the one formed from earthly concretion serves as a kind of vessel for the other derived from heavenly subtlety, when some force separates them—a separation called death—each returns to its own nature: what came from earth dissolves back into earth, and what came from the heavenly spirit endures and thrives forever, because the divine spirit is eternal.

Finally, Lucretius himself, forgetting what he was asserting and what dogma he was defending, wrote these lines: "It yields back to the earth what was from the earth before, but what was sent from the shores of the ether, the shining temples of heaven receive again." That was not something he ought to have said, he who argued that souls perish with bodies; but he was conquered by the truth, and true reason slipped in unawares. Moreover, the very conclusion he draws—that the soul is dissolved, that is, perishes at the same time as the body because they are born at the same time—is false and can be turned to the contrary. For the body does not perish at the same time; it remains intact for many days after the soul has departed, and often, when treated with medicine, it endures for a very long time. If, just as they are born together, they were to perish together, the soul would not suddenly depart and leave the body deserted; instead both would dissipate at the same moment, and the body would melt away and perish as quickly as the soul departs—indeed, with the body dissolved, the soul would vanish like liquid spilled from a broken vessel. But if the earthly and fragile body does not immediately dissolve into the earth and decay after the soul's departure, because it has that origin, then the soul, which is not fragile, remains forever, because its origin is eternal.