Defines nature as “a species which can’t be divided into other species” (154, quoting PG 94, col. 593).
Hypostasis: existence by itself (155).
“The Word has the initiative in the work of the Incarnation, and it is evident that the theory of enhypostasis while asserting and underlying Christ’s humanity, shows in an unequivocal way the primordial greatness of the divinity” (156). No one will accuse John of Damascus of being a monothelite; in fact, his statement appears to be a restatement of the instrumentalization thesis. Calvinists never say that Christ’s divinity overrides his humanity, or that the Holy Spirit mechanistically does so. But if Calvinists are to be accused of monothelitism because the divine nature has precedence over the human nature, then the charge must also extend to John of Damascus.
Jesus’s hypostasis: “constitutes or represents, in a sense, the whole of mankind” (160). Reformed would say that Jesus represents the whole of mankind, but on covenantal not metaphysical grounds.
original sin: “Sin is not in nature but in the free choice” (162). “The Greek Fathers conceived original sin as first of all hereditary mortality that mainatined mankind under the devil’s control” (162-163). The consequence of the sin is that the soul submitted to the body.
John goes on to state that Christ only assumed the incorruptible passions like hunger and death, and not the passions leading to sin. Interestingly, this isn’t that far removed from the Reformed contention that sin is accidental to the human nature and not a positive principle (cf Charles Hodge).