Is it Spirit of God or Spirit of Christ?
The Spirit of Christ
In the book of Romans, Paul wrote about the “Spirit of Christ” and the “Spirit of God” (Ro 8:9,10). In the King James Version, he also speaks of the “Spirit of Life” (Ro 8:2 KJV). Jesus spoke of One who would comfort, advocate for us and be in us, the “Spirit of Truth” (John 16:13). And, in the Book of Acts (Acts 2:4) we read of the “Holy Spirit.” So, how many “Spirits” (from God) are there?
Paul’s answered this for the Ephesians:
4 There is one body and one Spirit, just as you were called to one hope when you were called; 5 one Lord, one faith, one baptism; 6 one God and Father of all, who is over all and through all and in all.Ephesians 4:4-6
It is very clear from the context of the entire chapter of Romans 8, that Paul is using different terms to describe the same “Spirit of God.” The slight changes refer to the different work that the Holy Spirit performs. This is significant because every born again believer has the Spirit of God living in them (1Co 3:16 CSB). They may at times not be “filled” with the Holy Spirit and consequently be more filled with their own desires. This may be what Paul meant in Romans 8:5 “Those who live according to the flesh have their minds set on what the flesh desires; but those who live in accordance with the Spirit have their minds set on what the Spirit desires.”
Some pentecostals argue that, in Acts 2:4 the “Holy Spirit” came upon the believers and they “were filled with the Holy Spirit and began to speak in other tongues as the Spirit enabled them.” They may expand this to say that (in reference to Romans 8:11), unless one has experienced the gift of being “filled with the Holy Spirit” and “[spoken] in tongues,” they will not go in the rapture. Others go so far as to teach that you are not fully “saved” unless and until you speak with tongues.
Although we acknowledge that believers can (and should) be “filled” (baptized) with the Holy Spirit, and that they may “speak in tongues,” we do NOT believe that speaking in tongues is required in order to be born again.
In summary, there is only one Spirit of God and that other titles (e.g., “Spirit of Christ,” “Spirit of truth,” etc) are all referring to the third person of the Trinity, the Holy Spirit. There are also references in the Bible to the “spirit of man” (1Co 2:11 KJV), “spirit of the world” (1Co 2:12), etc, but they clearly are of a different character.