The three parts of the human person and the resurrection of the visible body

And since there are three things of which a human being consists—spirit, soul, and body—these are again spoken of as two, because the soul is often named together with the spirit. For a certain part of the same soul, the rational part, which beasts lack, is called spirit. Our principal part is the spirit; next, the life by which we are joined to the body is called soul; finally, the body itself, since it is visible, is our last part. Now this whole creation groans and is in labor until now (Romans 8:22); yet it has given the firstfruits of the spirit, because it has believed God and is already of good will. For this spirit is also called mind, about which the apostle says: “With my mind I serve the law of God” (Romans 7:25). He also says in another place: “For God is my witness, whom I serve in my spirit” (Romans 1:9). But the soul, when it still desires fleshly goods, is called flesh and resists the spirit—not by nature, but by the habit of sins. Hence it is said: “With my mind I serve the law of God, but with my flesh the law of sin” (Romans 7:25). This habit has been turned into nature through the mortal generation brought about by the sin of the first human being. Therefore it is written: “And we too were once by nature children of wrath” (Ephesians 2:3), that is, of punishment, through which it came about that we serve the law of sin. But the nature of the soul is perfect when it is subjected to its own spirit and when it follows the spirit that follows God. Therefore the animal human being does not perceive the things that are of the Spirit of God (1 Corinthians 2:14). But the soul is not subjected to the spirit for good action as quickly as the spirit is subjected to God for true faith and good will; rather, its impulse, by which it flows away into fleshly and temporal things, is sometimes reined in more slowly. But since the soul itself is also cleansed, receiving the stability of its own nature when the spirit rules—the spirit, which is its head, whose head is Christ—we must not despair that the body too will be restored to its own nature. But certainly not as quickly as the soul, just as the soul is not restored as quickly as the spirit, but at the proper time, at the last trumpet, when the dead will rise incorruptible and we will be changed (1 Corinthians 15:52). And therefore we believe also in the resurrection of the body—not only because the soul is repaired, which is now called flesh because of fleshly affections, but also this visible flesh, which is flesh by nature, whose name the soul received not because of nature but because of fleshly affections. This visible flesh, then, which is properly called flesh, must without doubt be believed to rise. For the apostle Paul seems to point at it as with a finger when he says: “This corruptible must put on incorruption” (1 Corinthians 15:53). For when he says “this,” he points his finger, as it were, at it. Now what is visible can be pointed at with a finger, since the soul can also be called corruptible; for it is corrupted by the vices of morals. And when we read, “and this mortal must put on immortality” (1 Corinthians 15:53), the same visible flesh is meant, because the finger is again, as it were, pointed at it. For the soul can also be called mortal, just as it can be called corruptible because of the vices of morals. Indeed, the death of the soul is to apostatize from God: its first sin in paradise is contained in the sacred writings.