The doctrine of the Holy Spirit in the early church has a interesting development. In many ways, the Holy Spirit was the silent member of the Trinity. The Father and son took most of the focus of the church. However, as time progressed, the doctrine of the Holy Spirit came to focus. In short, the Holy Spirit is of the same substance of the Father and Son, that is, co-equal in every sense. In light of this, within the unity of God, there was also diversity. This idea of diversity has been emphasized by nearly all modern theologians.