Hi Mark, most protestants accept the first 6-8 councils as authoritive, one of those stated that “*n the Holy Spirit, Lord and giver of Life, proceeding from the Father through the Son.” Council of Nicea II (A.D. 787).
I am assuming that our Orthodox brothern are building their case on the word proceed in John 15:26 and would likely say that word is not applied to the spirit proceeding from the Son.
But when the Comforter is come, whom I will send unto you from the Father, even the **Spirit of truth, which proceedeth **from the Father, he shall testify of me:
But, in that same text above Jesus says that he sends the Spirit too. In the texts below the Spirit is spoken of as belonging to God “Spirit of God” and belonging to Christ, “Spirit of Christ” thus both the Father and Son have ownership. Since the Son of God is the living God, 2 Cor 3:3 would apply to him too, not just to the father.
2 Corinthians 3:3
You show that you are a letter from Christ, the result of our ministry, written not with ink but with the Spirit of the living God, not on tablets of stone but on tablets of human hearts.
You, however, are controlled not by the sinful nature but by the Spirit, if the Spirit of God lives in you. And if anyone does not have the Spirit of Christ, he does not belong to Christ.*