Whose Spirit is Holy?

I discovered this jewel in Scripture during my daily devotions and felt compelled to share it... 

The Holy Spirit, or Spirit of God, is also called the "Spirit of Christ" a couple of times in the New Testament. He is not just sent by Christ (John 16:7) as well as by the Father, but He is called the Spirit OF Christ, the same way He is the Spirit OF God. Not simply sent by God or Christ, but is really a member of the Godhead, of the Trinity that includes both the Father and the Son. 

In I Peter 1:9-12, it says that the Spirit of Christ was in the prophets, indicating to them and testifying of His sufferings and the glory that would follow. A few verses later, he uses interchangeably the word Holy Spirit. 

Romans 8:9 also shows the interchangeable name: Spirit of God / Spirit of Christ: "However, you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. But if anyone does not have the Spirit of Christ, he does not belong to Him."

Of course, we know from all throughout scripture that it was God speaking through the prophets (Hebrews 1:1, for example), and that they wrote as they were driven by the Holy Spirit. So it's interesting to read here both Paul and Peter calling the Holy Spirit both the Spirit of God and the Spirit of Christ. 

Here are three other places where the Spirit is referred to Christ Jesus: 

Galatians 4:6 "Because you are sons, God sent the Spirit of his Son into our hearts, the Spirit who calls out, 'Abba, Father!'" (see Mark 14:36).  

Acts 16:7 "And after they came to Mysia, they were trying to go into Bithynia, and the Spirit of Jesus did not permit them."

Philippians 1:19 "For I know that this will turn out for my deliverance through your prayers and the provision of the Spirit of Jesus Christ." 

This is more than merely a linguistic variation.  Peter, Luke, and Paul in three separate letters all refer the Spirit to Christ.  The language used is the exact same language used to refer the Spirit to God: "Spirit of God" = pnevma theou, while "Spirit of Christ" = pnevma Khristou; "Spirit of His Son" = pnevma uiou avtou, etc.  The reference to God and Christ is even used interchangeably.  

What, then, can we conclude from these passages?  If Jesus is not God, and neither is the Holy Spirit, then we have a puzzle on our hands and can argue only by stretching an alternate translation out of these straightforward words.  However, if Jesus is God, and the Spirit is the third member of the Trinity, then it makes perfect sense that God's Spirit is also Christ's Spirit, Who proceeds from the Father and the Son (Jn. 14:16, Jn. 14:26, Jn. 16:7), in Whom we serve God (Rom 1+9) who demands that we serve Him alone (Lk. 4:8) and serve no created thing (Rom. 1:25).