The "one Spirit" of Ephesians 4:4 has been interpreted—and often ignored—in so many ways that many do not know where to begin to know Who the one Spirit is. I believe the evidence is available to say that Paul is referencing the One called the Holy Spirit. He is a Being Who possesses Godhood—divine nature (Matthew 28:19; Acts 5:3–4; 2 Corinthians 13:4)—which nature is possessed by only two other Beings: God the Father and God the Son. Space in this article will not allow for us to dig into all that the Holy Spirit is doing and has done, but hopefully I can challenge you to want to dig deeper into the Bible to find out Who He really is.
The sad truth is that a survey of the religious world will net us a variety of beliefs and views as to Who the one Spirit is and what He does. For example, the "Holy Spirit" of Pentecostalism is an emotional force that must be received in order for one to know he is saved; yet, the actual evidence of such a reception is very subjective and unbiblical. Another example is the "Holy Spirit" of Calvinism, which teaching finds itself in much of Presbyterianism and some Baptist doctrine. The idea is that God chooses individually who will be and will not be saved. Then, He uses the irresistible force of the Holy Spirit to denote one who is chosen.
Furthermore, the Holy Spirit does not provide people with the ability to speak gibberish which they refer to as "tongues;" however, there was a day in which the Holy Spirit gave individuals the ability to miraculously speak other languages (actual "tongues") without having prior training or rearing in those languages (Acts 2:4–11; 1 Corinthians 12–14). Also, the Holy Spirit does not directly induce emotional feelings which "direct" people to do certain things; however, the Words He has revealed to us through the Bible (John 16:13; 2 Peter 1:3, 20–21; Jude 3) should cause us to have emotions such as godly sorrow, which leads to repentance (2 Corinthians 7:10). Finally, the Holy Spirit does not cause our bodies to convulse, jump, bounce, roll on the floor, run, or yell as some in the religious world claim; however, the Scriptures He has breathed can teach us what is right, what is wrong, how to avoid the wrong, and how to do that which is right (2 Timothy 3:16–17).
I once participated in a "Bible class" where the "teacher" began by saying, "Today, we will discuss our opinions of the Holy Spirit." It was one of the most confusing and frustrating classes of which I have ever been a part. A survey of the religious world will yield multiple "Spirits," but the Bible says there is "one Spirit" (Ephesians 4:4). Will you believe the religious world, or the Bible?
Clifton preaches for the Coldwater Church of Christ in Coldwater, MS