Römer 8:9

But ye are not in the flesh, but in the spirit, if so be that the Spirit of God dwell in you--This does not mean, "if the disposition or mind of God dwell in you"; but "if the Holy Ghost dwell in you" (see Co1 6:11, Co1 6:19; Co1 3:16, &c.). (It thus appears that to be "in the spirit" means here to be under the dominion of our own renewed mind; because the indwelling of God's Spirit is given as the evidence that we are "in the spirit"). Now--"But." if any man have not the Spirit of Christ--Again, this does not mean "the disposition or mind of Christ," but the Holy Ghost; here called "the Spirit of Christ," just as He is called "the Spirit of life in Christ Jesus" (see on Rom 8:2). It is as "the Spirit of Christ" that the Holy Ghost takes possession of believers, introducing into them all the gracious, dove-like disposition which dwelt in Him (Mat 3:16; Joh 3:34). Now if any man's heart be void, not of such dispositions, but of the blessed Author of them, "the Spirit of Christ." he is none of his--even though intellectually convinced of the truth of Christianity, and in a general sense influence by its spirit. Sharp, solemn statement this!

The apostle, having fully explained the doctrine of justification, and pressed the necessity of sanctification, in this chapter applies himself to the consolation of the Lord's people. Ministers are helpers of the joy of the saints. "Comfort ye, comfort ye my people," so runs our commission, Isa 40:1. It is the will of God that his people should be a comforted people. And we have here such a draught of the gospel charter, such a display of the unspeakable privileges of true believers, as may furnish us with abundant matter for joy and peace in believing, that by all these immutable things, in which it is impossible for God to lie, we might have strong consolation. Many of the people of God have, accordingly, found this chapter a well-spring of comfort to their souls, living and dying, and have sucked and been satisfied from these breasts of consolation, and with joy drawn water out of these wells of salvation. There are three things in this chapter: I. The particular instances of Christians' privileges (v. 1-28). II. The ground thereof laid in predestination (Rom 8:29, Rom 8:30). III. The apostle's triumph herein, in the name of all the saints (Rom 8:31 to the end).

8:9 You are controlled by the Spirit: In contrast to unbelievers, who continue to live under the domination of Adam’s sinful nature, believers are directed in their lives by the Holy Spirit. The Spirit does not take away human initiative or make it impossible for believers to sin. However, as the most powerful force in believers’ lives, the Spirit makes it possible for them to resist the continuing power of sin.