This homily, once falsely ascribed by some to Saint Augustine, the monks of the congregation of Saint Maur rightly rejected into the appendix of that same doctor's sermons. No less falsely was it attributed to Saint Ambrose, both by certain others, and by him who transcribed it into the Theodoricensian codex. But there are in it certain things quite like those which Saint Maximus, treating of the same mystery, embraced in his homilies. And so I judge Maximus to be likewise the author of this one. In which opinion I am the more confirmed, since I read it referred to Maximus himself in two most ancient codices, that of Saint Dalmatius and the Taurinensis. Beloved, the festivity of our vows ought by now to be known to your holiness.
For what and by what reason we should observe, we learn thoroughly from the celebration itself. For when a solemnity that has passed is retraced again in its own footsteps, we become more instructed by celebrating it more often. Let us therefore keep Pentecost today, that is, the fiftieth day from the Lord's resurrection; not that on this day, as many suppose, the Savior ascended to the heavens. For after his resurrection, having tarried with the apostles, on the fortieth day he returned to the right hand of God the Father; as Luke the evangelist says: 'To whom also he showed himself alive after his passion, appearing to them through forty days' (Acts 1).
For the course of forty days, then, the Savior showed his converse to his disciples, namely that we might rejoice by the grace of his resurrection for as great a number as we had wept for the injuries of his passion, and that we might be refreshed for the same span of days by his presence as we fast in his absence. Not today, therefore, did Christ ascend to heaven, but the Spirit of Christ descended from heaven, as the Lord himself, promising, said: 'But when I shall have ascended to the Father, I will send you the Paraclete, the Spirit of truth, and he shall teach you all things' (John 16 and 14). A great grace plainly, a twofold joy: that we do not lose the departing Christ, and we possess the coming Spirit. For we retain the one by the merit of faith, this one by the access of sanctification.
'When I shall have gone to the Father,' he says, 'I will send you the Paraclete' (John 16). For we believe the Son has come to the Father, when we see the Paraclete has descended to the apostles. For we believe him to reign in the heavens, whom we perceive to bestow holy gifts upon the earth, as it is written through the prophet: 'Ascending on high, he led captivity captive, he gave gifts to men' (Psalm 68). The victor indeed is rewarded, the victor bestows gifts; whence the Savior too, victor over the devil after his triumph, enriched with a blessing also the disciples whom he freed from captivity. And he freed us when for our rising again he closed the underworld through himself; he enriched us when for our reigning he unbarred the heavenly things to us through the Paraclete.
And by certain steps, as it were, of advancement, then we learned to return from death to life; but now we are taught to ascend from the earth to the heavens; as it is written: 'He himself shall teach you all things' (John 14:26). What does the Holy Spirit teach? Assuredly he knows how to teach that which is holy. What does the Paraclete teach us? That indeed he teaches which the Savior says: 'I have many things to say to you, but you cannot bear them now; when that Spirit of truth shall come, he will teach you all things' (John 16:12). A good master, therefore, is the Paraclete, because he teaches the things which Christ reserved to be taught. For this the Holy Spirit teaches, which the Lord says he has to be taught. A good master plainly, who is the executor of the Savior's precepts.
It is necessary, therefore, that his nature be of one substance with Christ, since we see it to be of one doctrine with Christ. And therefore, beloved, let us cleanse ourselves from all defilement of the flesh, that we may be able to merit and receive the Holy Spirit. If we relinquish this world, we shall receive, like the apostles, a like Paraclete, that is, the Spirit of truth, whom the Father will send you; for there is no respect of persons with God the Father, but the things promised to the apostles profit us also, if we perform the works and desires and acts which the apostles did.
But if by fulfilling the immaculate law of the Lord, which converts souls, we accomplish his commandments, we commit ourselves as heirs of the Lord and coheirs of Christ to an everlasting inheritance and to the dwelling of the angels, with the grace of Christ; which may he himself deign to grant, who lives and reigns for ever and ever. Amen.