What Pentecost Brought
Pentecost brings to light not only that Christ has lived and has done something but that he lives now and is now at work in the church. Pentecost is not only when Christ poured out on the church the gift of the Spirit; it is also the coming to the church of Christ himself, as the life-giving Spirit. On Pentecost, when Jesus baptizes with the Holy Spirit, we may say, he baptizes with himself, his own presence. The gift of the Spirit is the gift of Christ himself, the glorified Christ.
Richard Gaffin, The Holy Spirit and Eschatology