Dearly beloved, the heart of all Catholics knows that we must venerate today's solemnity among the special feasts: there is no doubt how much reverence is due to this day, which the Holy Spirit has consecrated with the matchless wonder of his gift. In fact, this is the tenth day since the day in which the Lord rose to the heights of heaven to take his seat on the right hand of the Father and the fiftieth day since his resurrection. It has shone for us in Him from whom it began, containing within it the great mysteries of the old and new sacraments: in them it is clearly declared that grace was pre-announced through the law and the law was completed through grace. In fact, just as the Jewish people liberated from the Egyptians were given the law on Mount Sinai fifty days after the sacrifice of the lamb (cf. Ex 19:17), so, after Christ's passion, in which the real Lamb of God was sacrificed, the Holy Spirit came down on the apostles and on the multitude of believers fifty days after his resurrection, so that conscientious Christians might recognise that the beginnings of the Old Testament were at the service of the Gospel principles, and that the second covenant was founded by the same Spirit who instituted the first. In fact, as apostolic history testifies, "when the day of Pentecost had come, they were all together in one place. And suddenly a sound came from heaven like the rush of a mighty wind, and it filled all the house where they were sitting. And there appeared to them tongues as of fire, distributed and resting on each one of them. And they were all filled with the Holy Spirit and began to speak in other tongues, as the Spirit gave them utterance" (Acts 2:1-4). How fast the discourse of wisdom is, and where God is the teacher how quickly one learns what is taught! One does not turn to translation in order to listen, nor to exercise for practice, nor to time for study, but when the Spirit of truth blows where he wills (cf. Jn 3:8) the words of each nation become common in the mouth of the Church. Since that day showers of carisms and streams of blessings have watered every desert and every wilderness (cf. Is 35:6), for in order to renew the face of the earth (cf. Ps 103:30), "God's Spirit hovered over the waters" (Gen 1:2), and to dispel the old darkness flashes of a new light appeared, while from the splendour of sparking tongues sprang the ardent word of the Lord and his fiery destiny (cf. Ps 18:9), in which is found efficacy to enlighten and strength to burn in order to form minds and conquer sin. (Augustine of Hippo)