(Extracts from a sermon of the Feast. Cf. Opera Omnia, 1881.)
We shall say why he came, how he came and comes to us, this Holy Spirit. His comings are visible and invisible, according as he uses or does not use signs which have a relation to the internal effects produced. The invisible corning happens every day, because the Spirit breathes where he will, and even though his voice is heard, we do not know whence he comes or whither he goes, as the Lord said to Nicodemus (John 3. 8). There is no exterior movement, but at times we do notice it even physically within us (Ps. z8. 4-7).
2. Why did he come? For three reasons:
(a) Because he was unknown:
The Father was known, or at least could be known, in the whole world. The Word had been half-guessed at by some of the ancient philosophers, and, what is more, had manifested himself magnificently in Christ; but the Holy Ghost remained unknown, probably because there is no created likeness of his origin in the world.
(b) To show God's goodness and charity:
The magnificence of the Incarnation and redemption could not have been known were it not for the teachings of the Holy Spirit, who, having spoken by the mouths of the prophets, now makes clear for us those ancient figures. What would the Incarnation and redemption be to us unless we knew them? Our Lord announced a Paraclete who would give testimony of him and would teach us the truth on his behalf (John 15, 28; 16. 13).
(c) To complete the work of Christ:
How wonderful is the supernatural generation of the world! Christ left the seed—the apostles. But the Holy Ghost descended, spread his wings over them, and that divine warmth brings forth the new generation of eagles who launch themselves forth to overcome the world. In the same way as Christ was born of Mary through the power of the Holy Ghost, see here these sons of a virgin Mother, the Church, whom the Holy Ghost made fertile.
3. How did he come?
There is a profound mystery in the fact that the law and the consummation of the law were both given on the same day, at the foot of Mt Sinai and on Mt Sion. But what a difference between the two laws! One was a law of death, engraved on stone; the other was the law of grace, engrave on the hearts of men by the life-giving Spirit. Well has Jeremias described it: No, this is the covenant I will grant the people of Israel, the Lord says, when that time comes. I will implant my law in their innermost thoughts, engrave it in their hearts; I will be their God, and they shall be my people (Jer. 31. 33). An eternal law this, not like that of Moses, but written in living books, the apostles, in whom we read, not merely teachings, but also works and examples. A time is coming, the Lord says, when I mean to ratify a new covenant with the people of Israel, and with the people of Juda. It will not be like the covenant which I made with their Fathers, on the day when I took them by the hand, to rescue them from Egypt; that they should break my covenant, and I, their Lord, should abandon them (ibid.).
4. How does he come to souls?
He will also come to us if we strip ourselves of the old man, by his help. Just as we cannot change one of our black hairs into white, so the more efforts we make to advance in the spiritual life without his help, so much the more shall we sink in the flesh. Have no confidence in yourselves, but look to that mountain from which comes the help of the Lord, who made heaven and earth (Ps. 120. I). To do that we must first of all esteem it, then ask him for it; because no one makes an effort to acquire anything which he does not esteem.
You know that, apart from the spirit of God, there exist also those of the world and the flesh, entirely opposed to it. If you let your-selves be carried away by worldly desires and shameful pleasures, you can be sure that the Spirit does not dwell in you. Offer him a soul which is pure and at peace, and he will surely come to you at once.
Peace is necessary, peace in your consciences, which you will secure by renouncing the world : peace with your brethren, like those who were together in one place, awaiting the coming of the Paraclete : peace with God. Seek peace first of all, and the God of charity will be with you (2 Cor. 13. 11).