This Sunday we celebrate the coming of the Spirit, at Pentecost. But Genesis tells us that the Spirit was in the world from the beginning, moving upon the face of the waters at the creation of the world. In fact, the Spirit is all throughout the Old Testament. There were prophets and judges, and even kings, who were filled with the Spirit. For example, the Spirit of God came upon Balaam (Num. 24:2), Joshua (Num. 27:18), Gideon (Judges 6:34), Jephthah (Judges 11:29), Samson (Judges 13:25), Saul (1 Sam. 11:6), David (1 Sam.16:13), and others as well.
So why in the Gospel Reading does Christ say that he will send the Spirit? How does he send the Spirit if the Spirit was already in the world, in Old Testament times?
We should notice that, in the Old Testament, the Spirit is mentioned as coming only on a few particular people, for particular purposes marked out by God. But after the resurrection of Christ, when Christ sends the Spirit, the Spirit comes on every single one of those who say with their hearts that Jesus is Lord. Whatever other gifts the Spirit might bring to people, no one can say that Jesus is Lord without the Spirit, as the Second Reading explains.
Furthermore, after the resurrection of Christ, the coming of the Spirit is marked by the life, death, and resurrection of Christ. It is not just the Spirit of the Father; it is Christ’s spirit too. By being filled with Christ’s Spirit, those who receive that Spirit are unified with Christ.
So when the Spirit comes into the world in consequence of Christ’s sending, it comes on all of Christ’s people forever, for their whole lives. And its purpose is to unite them all with Christ, into the body of Christ.
So that is why the Spirit comes at Pentecost, to inaugurate the new age, which God promised long ago. Through his prophet Joel (2:28), God promised that in the messianic age God would pour out his Spirit on all his people; and then God himself would be the hope and the strength of his people (Joel 3:16).
We are included in that promise too, by God’s spirit dwelling in us, when we say with our hearts that Jesus is Lord.