John 7:39 note 1
391 The Spirit of God was there from the beginning (Gen. 1:1-2), but at the time the Lord spoke this word, the Spirit as the Spirit of Christ (Rom. 8:9), the Spirit of Jesus Christ (Phil. 1:19), was not yet, because the Lord had not yet been glorified. Jesus was glorified when He was resurrected (Luke 24:26). After Jesus' resurrection, the Spirit of God became the Spirit of the incarnated, crucified, and resurrected Jesus Christ, who was breathed into the disciples by Christ in the evening of the day on which He was resurrected (20:22). The Spirit is now the "another Comforter," the Spirit of reality promised by Christ before His death (14:16-17). When the Spirit was the Spirit of God, He had only the divine element. After He became the Spirit of Jesus Christ through Christ's incarnation, crucifixion, and resurrection, the Spirit had both the divine element and the human element, with all the essence and reality of the incarnation, crucifixion, and resurrection of Christ. Hence, the Spirit is now the all-inclusive Spirit of Jesus Christ as the living water for us to receive (vv. 38-39).