In Romans 8:9 Paul says, “You are not in the flesh, but in the spirit, if indeed the Spirit of God dwells in you. Yet if anyone does not have the Spirit of Christ, he is not of Him.” This verse indicates that the Spirit of Christ is the Spirit of God who dwells in us that we may be in the spirit. The Spirit of God and the Spirit of Christ are not two Spirits but one. Paul used these titles interchangeably, indicating that the indwelling Spirit of life in verse 2 is the all-inclusive life-giving Spirit of the entire Triune God. God, the Spirit, and Christ—the three of the Godhead—are all mentioned in verse 9. However, there are not three in us; there is only one, the triune Spirit of the Triune God (John 4:24; 2 Cor. 3:17; Rom. 8:11). The Spirit of God implies that this Spirit is of the One who was from eternity past, who created the universe and is the origin of all things. The Spirit of Christ implies that this Spirit is the embodiment and reality of Christ, the incarnated One. This Christ accomplished everything necessary to fulfill God’s plan. He includes not only divinity, which He possessed from eternity, but also humanity, which He obtained through incarnation. He also includes human living, crucifixion, resurrection, and ascension. This is the Spirit of Christ in resurrection, that is, Christ Himself dwelling in our spirit (v. 10) to impart Himself, the embodiment of the processed Triune God, into us as resurrection life and power to deal with the death that is in our nature (v. 2). Thus, we may live today in Christ’s resurrection, in Christ Himself, by living in the mingled spirit.
Romans 8:10 reveals that the Spirit of Christ is Christ in us to make our spirit life: “If Christ is in you, though the body is dead because of sin, the spirit is life because of righteousness.” In this verse the Spirit is not mentioned, for here the emphasis is that Christ today is the Spirit and that the Spirit of Christ is the very Christ in us. According to the fact, it is Christ; according to experience, it is the Spirit. In our experience of Him, He is the Spirit; in our worshipping of Him, calling on Him, and speaking of Him, He is Christ. We receive Him as our Savior and Redeemer, but He enters into us as the Spirit. As the Redeemer, He has the title Christ; as the Indweller, He has the title the Spirit. These are not two who dwell in us but one Dweller in two aspects.
“Christ...in you” is the crucial point of the book of Romans. In chapter 3 Christ is on the cross, shedding His blood for our redemption; in chapter 4 He is in resurrection; in chapter 6 we are in Him; now, in chapter 8 He is the Spirit in us.
Before we believed in the Lord, our spirit was dead. Now that we have Christ in us, our spirit is life because of righteousness. In our spirit is Christ the Spirit as righteousness, resulting in life. Moreover, we need to see that our spirit has not only been regenerated and made living; our spirit has become life. When we believed in Christ, He as the Spirit of life came into our spirit and mingled Himself with it; the two spirits thereby have become one spirit (1 Cor. 6:17). Now our spirit is not merely living but is life.
The Spirit of Christ is also the Spirit of the One who raised Jesus from among the dead, dwelling in us to give life to our mortal body. “If the Spirit of the One who raised Jesus from the dead dwells in you, He who raised Christ from the dead will also give life to your mortal bodies through His Spirit who indwells you” (Rom. 8:11). In this verse we have three matters. First, we have the entire Triune God—the One who raised Jesus from the dead, Christ Jesus, and His Spirit who indwells you. Second, we have the process required for His dispensing, as implied in the words Jesus (emphasizing incarnation), Christ (emphasizing crucifixion and resurrection), and raised (emphasizing resurrection). Third, we have His dispensing of Himself into the believers, as shown by the phrase give life to your mortal bodies, which indicates that the dispensing not only occurs at the center of our being but also reaches to the circumference, to our whole being.
The phrase give life to your mortal bodies does not refer to divine healing but to the result of our allowing the Spirit of God to make His home in us and saturate our entire being with the divine life (Eph. 3:16-19). In this way He gives His life to our mortal, dying body, not only to heal it but also that it may be enlivened to carry out His will.