[Man is composed] of soul and body. Now whenever [one] performs one of the actions that are approved by God, he is called “spiritual”, and he is not named from his soul, but from another honor which is superior: the activity coming from spirit. For soul does not suffice for a correct action, if it does not take advantage of spirit’s aid. But just as he who serves the flesh is called “fleshy (or carnal) man”, so too the Apostle calls “natural” the man who attributes matters to human reasoning and does not acknowledge the activity of spirit.[1]
And again: whenever we correctly perform a virtue, we are called “spiritual”. But whenever we are overturned and perform an action which is contrary [to virtue], [he] names us “dust” on account of our base nature. And the Prophet says, "He will afflict earth with a word of his mouth”;[2] he is not talking about earth, but about sins. And again: “the whole earth became only one lip”;[3] he is [again] speaking of sins. And Abraham, in disparaging himself, [says]: “I am dust and ashes”. [4] And again: “His entrails are despised in his life”; [in this case] he is making reference to the womb.[5]
Souls of those who die violently[6] do not become demons, according to the opinion of the many, but those of sinners; their substance does not change but [their] choice imitates the vice of those [demons]. That is also what Jesus Christ used to say to the Jews: “you are of your father the devil”.[7]