Before his Resurrection and again before his Ascension, Our Lord promised his Apostles that he would send them from the Father, the Holy Spirit: and he spoke of the Holy Spirit not as something but as someone who would teach them and lead them into all truth.

When the Holy Spirit came to the Apostles on the Day of Pentecost and to their converts at their Baptism and Confirmation, the effect was remarkable.  They became new people.  Peter who had quailed at the voice of a maidservant in the high priest’s house now openly rebuked the high priest himself before his own Council.  Saul, the brutal persecutor, became Paul the Saint and the same thing happened in different ways and varying degrees in the lives of countless Christians all over the Roman Empire.

It was clear that a new Power had come to them which was forming in them the character of God and that this Power, the Holy Spirit, must be personal to do this.  So their own experience day by day proved the truth of Our Lord’s promise.