The many efforts made to explain the mystery were speculative rather than theological. These efforts invariably ended in the denial of the unity of the Godhead, or denial of the personal distinctions within the Godhead. The real difficulty in explanation lies in the relation in which the persons in the Godhead stand to the divine essence, and to one another. This is a difficulty the church cannot remove, but can only try to render a proper definition of terms. The church has never tried to explain the mystery of the Trinity, but has only sought to formulate a doctrine as free from error as possible.
Perhaps you have wondered why we have spent so much time in discussing the Doctrine of the Trinity when the lesson is supposed to be on the Holy Spirit.
Well, it is necessary to understand what the Doctrine of the Trinity is, in order to realize the proper importance of the Holy Spirit. The Holy Spirit is the name applied to the third person in the Trinity. We are told in John 4:24 that God is a Spirit. The Old Testament uses the word “Spirit” many times without any qualification, but also speaks of “the Spirit of God,” or the “Spirit of the Lord” but employs the term “Holy Spirit” only in the Psalms. The New Testament seldom uses the word “Holy” in describing God, but frequently uses the word Holy in relation to the Spirit. This was perhaps because it was the Holy Spirit that took up residence in the hearts of men and led them unto God.
It is only when we realize the importance of the Holy Spirit as being equal to God and the Son in the divine essence that we can begin to look for its action in our lives.
The term Holy Spirit does not indicate as much personality as the term God or Son. That a person is meant as a description of the Holy Spirit is indicated by the fact that Christ said that He would send the Holy Spirit as a comforter, and since the Holy Spirit would bear the same relation to the Christians as Christ, another person in the form of the Comforter is plainly indicated. The relation of the Holy Spirit in the Trinity to the other persons is one of equality, and the Holy Spirit is as close to God as the soul of man is to man.