(15:26-27) The Holy Spirit proceeds from the Father and the Son. The mission of the Spirit is not to bear witness to himself, but to the resurrection of the Son. (16:4b-15) Christ comforts his disciples before his death by promising to send them the Holy Spirit who will guide them into a deeper understanding of Christ's role in God's mission. Christ is present with us through the Holy Spirit. It is not easy to answer the question, who is the Holy Spirit? We seldom ask, who is the Holy Spirit?—and that tells us something about our understanding of the Spirit. The Spirit is usually associated with something rather vague, unseen, and unfelt. Our minds, it seems, are unable to connect the Spirit with anything but unreality. God the Father is not hard for us to understand and even to picture; we know what a father is like. God the Son is easier to picture. We have thousands of representations of Jesus Christ the man from Nazareth, as a baby, as a man, teaching, healing, praying, suffering, dying, rising, reigning. But the Spirit is a challenge. How do you portray a Spirit? As a bird perhaps, but that is obviously little more than a simple illustration. We describe “who” the Holy Spirit is by describing what he does. The primary work of the Holy Spirit is that he calls us to the Gospel; gathers us in Christian community; enlightens us to the work of the Triune God; makes us holy (set aside) for Christ’s mission of reconciliation; and, preserves our faith in Christ throughout our earthly pilgrimage.