“. . . in Romans 8:9,10 those who ‘belong to the Spirit’ (v. 9d, i.e., are ‘in Christ’) are at the same time those ‘in the Spirit’ (v. 9a), those in whom ‘the Spir­it of God dwells’ (the Spirit in you, v. 9b), and those in whom Christ dwells (‘Christ in you,’ v. 10a), all because of, to empha­size it again, who the Spirit is (the Spirit of Christ–v. 9c), and who Christ is (the life-giving Spirit–I Cor. 15:45).” (Richard B. Gaffin, Jr., Perspectives on Pentecost, p. 21).

“. . . what Paul [means] by the Spirit, is not the mind or under­standing. . . but a celestial gift; for he shows that those are spiritual, not such as obey rea­son through their own will, but such as God rules by his Spirit. (John Calvin, Commentary on Romans at 8:9).