Dark shadows fall over the closing pages of John's Gospel. For our Lord himself, there is the shadow of the cross; for the disciples, the shadow of his imminent departure. He is leaving them to return to the Father, and they are utterly distraught. It is to this distress that Jesus addresses the words of John 16:7: "It is to your advantage that I go away, for if I do not go away, the Helper will not come to you. But if I go, I will send him to you."
The words make two remarkable points. First, unless he goes away "the Helper" will not come. There is a divine order in the work of redemption, and in terms of that order there can be no Pentecost before Calvary. It is not simply that without the cross neither the disciples nor the Helper would have any witness to bear. There is a deeper reason: Only when Christ has redeemed us from the curse of the law can we receive the promised Spirit (Galatians 3:14).
Before there can be communion, there must be reconciliation. But the converse is also true. Wherever Christ redeems, the Spirit ministers. This is why salvation can never be merely an external imputation of Christ's righteousness. It is also profoundly inward. Wherever the blood is sprinkled, the Spirit transforms.