The Etymology of “Holy Spirit”

Ruach Hakodesh - the holy breath or wind of God, his active presence and power in creation and prophecy

Ruach means breath, wind, or spirit. In Gen 1:2, the ruach of God hovers over the waters. The Spirit anoints judges, kings, and prophets. Joel 2:28 promises the Spirit will be poured out on all flesh.

Pneuma Hagion - the third person of the Trinity, sent by the Father and Son to indwell believers

John 14-16: Jesus promises the Paraclete (Advocate/Helper) who will convict, guide, and glorify Christ. Acts 2: Pentecost inaugurates the age of the Spirit. Paul: the Spirit is the down payment of the age to come.

Spiritus Sanctus - the third person of the Trinity, co-equal with Father and Son, proceeding from both

The Nicene Creed (325) was unclear on the Spirit; the Council of Constantinople (381) affirmed: the Lord and Giver of life, who proceeds from the Father. The filioque (and the Son) was added by the Western church, causing the Great Schism.

The Spirit as the internal testimony illuminating Scripture and applying salvation to the believer

Calvin emphasized the testimonium Spiritus Sancti internum (internal testimony of the Holy Spirit) as the basis for Scripture authority. The Spirit who inspired the text illuminates its meaning to the reader.

The Spirit as the presence of the future - the power of the coming age breaking into the present

Moltmann (The Spirit of Life) and Pentecostal/charismatic renewal have re-centered the Spirit in modern theology. The explosive growth of Pentecostalism globally is the most significant Christian development of the 20th century.