Christian theology develops Old Testament references to the Spirit of God as active in the creation of the world (Genesis 1:2), as giving life to man (Genesis 2:7; 6:3), and as promised to "the Servant of the Lord" (Isaiah 42:1-3). The New Testament sees this promise as fullfilled in the life of Jesus (for example Luke 3:21; 4:18-20) but bases its understanding of the Spirit more directly on those texts of the Old Testament in which the Spirit of God is promised to the whole people of Israel.
The writings of John and Paul are especially important for the church's later theology of the Holy Spirit. For John, the Spirit is "another Counsellor," who assists the church in recalling and interpreting the words of Christ (John 14: 25-26) and through whom Christ is forever present to His disciples (14:16). At times Paul nks Christ and the Spirit so closely that it is difficult to distinguish between the two (II Corinthians 3:17: "The Lord is the Spirit"). He describes the Spirit as both "the Spirit of God" and "the Spirit of Christ" and attributes to the Spirit the function of uniting men with God through Christ (Romans 8:9-17).
During the 4th century Trinitarian controversies, when the principal issue was the full divinity of the Son, the church at first merely affirmed its belief in the Spirit (Council of Nicaea). Subsequent controversies, however, led to a fuller creedal statement on the divinity of the Spirit and to considerable theological speculation on the Spirit's relation to the Father and the Son within the Trinity. During this period St. Augustine significantly influenced all later Western theology by his description of the Spirit as the bond of love that unites Father and Son.
In the 9th century the so-called Filioque became a major focus of doctrinal differences between the Eastern and Western churches. Eastern theologians protested against the Western church's addition of the expression "and [from] the Son" (Filioque) to the traditional creedal assertion that the Spirit "proceeds from the Father." The Council of Florence (1439) sought to resolve the dispute, but the Eastern church has never accepted the solution proposed by this council.
Contemporary Theological Emphases
Contemporary theologians have been especially concerned with the New Testament's understanding of the Spirit as the unifying bond and sanctifying force in the church and with the relation between the charismatic (or "spiritual") and the institutional aspects of the church's life. With respect to the "personality" of the Holy Spirit, some contemporary Protestant theologians have argued that the term "person" suggests a multiplicity of divine beings, which the doctrine of the Trinity was meant to exclude. They have suggested that the "persons" of the Trinity be described as "modes" or "ways of God's being God." Roman Catholic theologians generally have retained the traditional terminology but agree that the term "person" must be understood in such a way that the concept of the perfect unity of God is clearly maintained.