Baptism of The Holy Spirit

The giving of the Spirit is related to the person and work of Christ. Just as Jesus undoubtedly had the Spirit before his baptism, so the disciples had the Spirit before Pentecost. At his baptism, the Spirit came on Jesus with respect to his task as the Savior. The disciples, if they were believing Jews, had the Spirit with respect to the foreshadowing of Jesus in the Old Testament Covenant. As disciples of Jesus, their faith in him as their Master was a divine gift and therefore of the Spirit. At Pentecost the Holy Spirit comes upon them for the first time with respect to the fully revealed Christ. This can happen only after he is glorified (Jn 7:39).

Graeme Goldsworthy, According to Plan, Pg. 214