During the last supper—we have heard it from the gospel—Jesus promises the coming of the Holy Spirit. He calls him the “Advocate”—“another Advocate,” because the first Advocate is Jesus himself. He will remain with the disciples for ever; he will teach them everything and remind them of all that Jesus has told them.
Who is this mysterious figure? The disciples will understand it little by little, precisely with the assistance of the Holy Spirit himself. He is God, like the Father and like Jesus. They are three; not three Gods, but only one God in three Persons—a mystery that we will contemplate next Sunday, the mystery of the Most Holy Trinity.
Jesus’ promise is fulfilled ten days after his ascension into heaven, fifty days after his resurrection from the dead, on the Jewish festival of Weeks. While the apostles were praying in the Cenacle, that is the Upper Room where the last supper had taken place, at around nine in the morning, “suddenly there came from the sky a noise like a strong wind, and it filled the entire house in which they were. Then there appeared to them tongues as of fire, which parted and came to rest on each one of them. And they were all filled with the Holy Spirit and began to speak in different tongues, as the Spirit enabled them to proclaim.”
Through these words of the Acts of the Apostles we can understand something more about the Holy Spirit. He arrives like a wind. Both in Hebrew and in Greek the word for “wind” and “Spirit” is the same; which means that the Holy Spirit is really like wind: you do not see it, but you can feel it; sometimes the wind is so strong that it can uproot a tree. Likewise, the Holy Spirit can be compared to breath: even in this case, you cannot see breath, but you know how important it is for you, because it allows you to live. When you breathe your last, you are dead.
Often in the gospel the Holy Spirit is also compared with water. Water is, among the natural elements, the most necessary for living: you can endure a long time without eating; but you cannot without water. That is why, in the Creed, we call the Holy Spirit the “giver of life.” On the contrary, the Acts of the Apostles tells us that “there appeared to them tongues as of fire, which parted and came to rest on each one of them.” So the Holy Spirit is like fire. Fire can firstly be used to purify. Usually, to wash we use water; but not everything can be cleaned by water; if you have to purify a noble metal, you have to put it in the furnace, so that the impurities may be separated from the metal. In the same way, the Holy Spirit purifies us from sin and makes us holy, like him. Moreover, fire is usually compared with love, because love warms hearts: when one is unable to love, we say that he is cold. Well, the Holy Spirit is the fire that kindles our hearts and enables them to love, not so much with a human love, but with a divine love. Yes, he can do this, because he is Love personified: he is the love that joins the Father and the Son; and he is not just a feeling, but a Person.
When the Holy Spirit came down on the apostles, they began to speak in different tongues and the people present in Jerusalem, coming from different countries, were able to understand them. This is the first miracle of the Holy Spirit: he removes the divisions among men caused by sin, and makes of all humanity only one people. It is the mystery of the Church, that we are experiencing in this moment: we are from every part of the world, but with the same faith; we speak different languages, and yet we understand each other, because we are only one people, the people of God.
But the greatest miracle of the Holy Spirit is that of which Saint Paul reminds us in the second reading: “You did not receive a spirit of slavery to fall back into fear, but you received a spirit of adoption, through which we cry, ‘Abba, Father!’ The Spirit itself bears witness with our spirit that we are children of God.” No more slaves, but children, children of God! Thanks be to God!