The soul's three parts and the four virtues
The treatise opens by listing the parts of the soul and the virtues on which the intellect is enthroned, then describes the threefold law and the body-soul relationship.
The soul has three parts: the appetitive part, the spirited part, and the rational part. The most sacred intellect is enthroned on four virtues: understanding, courage, justice, and temperance.
The law is threefold: natural, written, and spiritual in grace. The body is fourfold, composed like a cosmos, while the soul within it is tripartite, prefiguring the Holy Trinity and giving life to the body through its activities. We say the soul is tripartite because it has a rational part, a spirited part, and an appetitive part. Through the rational part it thinks; through the spirited part it is angry with demons, acting courageously against them; and through the appetitive part it loves God.
Greek
Τῆς δὲ ψυχῆς μέρη γʹ. Ἐπιθυμητικὸν, θυμικὸν, λογιστικόν. Ἀρεταῖς δὲ τέσσαρσι
τεθρόνισται ὁ ἱερώτατος νοῦς· φρονήσεως, ἀνδρείας, δικαιοσύνης, σωφροσύνης.
‹95.232› Τρισσὸς ὁ νόμος. Φυσικὸς, γραπτὸς, καὶ ὁ ἐν χάριτι πνευματικός. Τετραμερές
ἐστι τὸ σῶμα, ὥσπερ τις κόσμος συνιστάμενον· τριμερὴς δὲ ἐν αὐτῷ ἡ ψυχὴ, προτυποῦσα
τὴν ἁγίαν Τριάδα, καὶ τοῦτο ταῖς ἐνεργείαις ζωοποιοῦσα. Τριμερῆ δὲ λέγομεν τὴν
ψυχὴν, ἔχουσαν λογικὸν, θυμικὸν, καὶ ἐπιθυμητικόν· ἵνα διὰ μὲν τοῦ λογικοῦ
λογίζηται· διὰ δὲ τοῦ θυμικοῦ ὀργίζηται τοῖς δαίμοσιν, ἀνδριζομένη κατ' αὐτῶν· διὰ δὲ
τοῦ ἐπιθυμητικοῦ ἀγαπᾷ τὸν Θεόν.