From Commentary on Romans (ca. 1265-1273)
Paul sets forth the state of the faithful “you are not in the flesh.”… Here he takes “flesh” as the vices of the flesh, as in 1 Cor. 15:50, “flesh and blood will not possess the reign of God.” Therefore he states, “you are not in the flesh,” that is, in the vices of the flesh, as if living according to the flesh… Second, he adds a condition, “If, nevertheless, the Spirit of God dwells in you,” namely through charity: (1 Cor. 3:16), “You are the temple of God, and the Spirit of God dwells in you.”
He adds this condition because, although they received the Holy Spirit in baptism, it could nevertheless happen that, due to sin’s approach, they would lose the Holy Spirit. Wisdom 1:5 states, “The Holy Spirit is rebuffed at the approach of wickedness.” This he shows that this condition should exist in them when he says, “If they do not have the Spirit of Christ, they are not his.” For just as something is not a member of the body that is not given life by the body’s spirit, so they are not a member of Christ who do not have Christ’s Spirit. 1 John 4:13, “In this we know that he remains in us because he has given us of his Spirit.” It should be noted that the Spirit of Christ and the Spirit of God the Father are the same…
One should consider what the apostle Paul said above about the Spirit of God and about the Spirit of Christ, although it is the same Spirit. First, he shows what we obtain from the Spirit, inasmuch as it is Christ’s Spirit. Second, Paul shows that we obtain from the Spirit inasmuch as it is God the Father’s, “Because if the Spirit of the one who raised Jesus from the dead,” etc, (Rom 8:11).
He states, therefore, that they who do not have Christ’s Spirit are not his. Thus, since you are Christ’s, you have Christ’s Spirit, indeed Christ himself dwelling within you through faith, according to Eph. 3:17, “That Christ might dwell in your hearts by faith.” But if Christ is thus in you, you must be conformed to Christ…
Paul adds, “The one who raised Jesus Christ from the dead will also give life to your mortal bodies.” He does not say “dead” but “mortal,” because in the resurrection not only will death – that is, the necessity of death – be removed from your bodies but also mortality – that is, the potential to die – as Adam’s body had before sin. For, after the resurrection our bodies will be thoroughly immortal. Isaiah 26:19, “Your dead will live; my slain will rise again;” Hos. 6:2, “He will give us life after two days.” This is the case “because of God’s Spirit indwelling” us, that is, in the power of the Holy Spirit dwelling in us. Ezk. 37:5, “The Lord God says to these bodies, “Behold I will send spirit into you, and you will live…
St. Thomas Aquinas (ca. 1225-1274) is sometimes described as the greatest thinker of the medieval Church. His various theological treatises, above all his Summa Theologica, seek to reconcile inherited Christian teaching with the newly rediscovered metaphysical writings of Aristotle. His Commentary on Romans is a text reconstructed from lectures he gave at the University of Paris near the end of his life. His modern feast day is January 28. This text has been slightly adapted for contemporary readers.
