Now to this phrase, "May the God of peace sanctify you in all ways," or "in all things," or, if we flex the Greek text, "give you a full and perfect holiness;" He is called "God of peace," because we were reconciled to him through Jesus Christ, "who is our peace, who has made the two peoples one," and, as the apostle said in another place, is "the peace of God which surpasses all comprehension, that keeps the hearts and minds of the saints." But he who was sanctified and is perfect in all things, "keeps his spirit, his soul, and his body without blemish for the day of the coming of the Lord," and uses his bodily members for the purposes for which they exist: his hands to work, his feet to walk, his eyes to see, his ears to hear, his teeth to eat, his stomach to digest meat, his bowels to order to avoid what is naturally leftover. Thus it is when all members of one's body are whole and perfect.
But is it credible that Paul, in making this blessing-vow to heaven, expects Jesus Christ, on judgment day, to find the faithful individual's body entirely intact? Does not death reduce everything to dust? Or if there are still a few, as some authors claim, that are still alive and kicking, do they not invariably have some defect? Consider especially the bodies of martyrs, even those whose eyes, or nose, or hands have been torn or cut off, for the sake of Christ. Therefore what the apostle meant by a "whole body" is, as I have said elsewhere, that which remains attached to the head, verily, the leader from whom all parts of the body are united and bound together, according to the effective increase of the body of Jesus Christ. But this body is none other than the Church, and anyone who has a close union with the head of this body must also assist in the maintenance of all other members in the whole body, as far as human frailty can afford. And to do that, they must maintain the integrity of the soul, so as to say, "Bless the Lord, O my soul, who heals all your infirmities," and it is written, "He sent his word and He healed." We also maintain the integrity of the mind when we live according to spiritual things; we live by the Spirit, and thus we follow with docility the guidance and impressions from the Spirit, so that we may mortify by the mind the works of the flesh, and so that we produce the fruits of the Spirit, by which I mean love, joy, peace, and so forth.
Here is another explanation that we can give to the words of the Apostle Paul. As Solomon set forth a proverb by describing things in three ways, so our teachings and applications, conducted thoughtfully and carefully, may be set forth to expound the truth for those who question us. We can describe the three ways by which the instructions and regulations of Scripture are set forth in our hearts. First there is the literal and historical sense. Second, there is the moral sense. And, finally, it may be taken in the spiritual sense. In the literal sense, we are dealing simply with the facts of the story as we follow a sequence of events being narrated. In the moral sense, we leave the literal meaning and consider larger and nobler ideas that are expressed for the regulation of our morals, and for our edification, though grounded in physical matters pertaining to the Jewish people. In the spiritual sense our objective is something even more sublime; we abandon all the earthly things, and simply look for what is said about the heavenly things, and the joy that is prepared for us; looking at all the good things in life is like a shadow in comparison to the adamantine happiness that is ours in that day. Jesus Christ, by His peace, will sanctify and perfect those who are happy in this situation, that is, those whose sole occupation is to take care to preserve the integrity of their body, their soul and their spirit, and to acquire a perfect knowledge of truth, and the triple-knowledge of which Solomon speaks.
Many, focusing simply on the letter, understand as pertaining to the resurrection what the Apostle Paul says, that we must keep our mind, our soul, and our body spotless for the day of the coming of the Lord. Some of them have claimed that this passage proves that man is composed of three kinds of substances: a spirit, which is the principle of their feelings and their thoughts, a soul, which is the source of his life, and of a body, which serves as an instrument for all external actions. There are others who claim that man is composed of a core and a body, and that the "spirit" that we add is not a substance but a principle which, according the different effects it produces, is sometimes called spirit, or feeling, or thought, because there is no man in so many different substances that give them different names. And when they encounter the passage of Scripture, "Spirits and souls of the righteous, bless the Lord," they reject it by saying that these words are not found in the Hebrew text. For me, as I said earlier, I think that the "spirit" which remains blameless with soul and body, must not be interpreted by us to mean the Holy Spirit, whose substance is imperishable, bur rather His gifts and graces, which lights are capable of being extinguished in us, if we make a poor, rather than good, use of them.