In the Turin codex this sermon is numbered among the homilies of Saint Maximus as the twentieth, and was published from the Ambrosian codex by Mabillon and Muratori in the places indicated above. After the festival of the Lord's Ascension, dearest brethren, we today celebrate the holy mysteries of Pentecost, so that, just as we rejoiced that a man ascended to heaven for us, so now let us exult that for our sake the Holy Spirit descended from heaven. Christ went to the Father, the Paraclete came from the Father, so that we may not doubt that all the gifts of eternal salvation are conferred upon us by the disposition and will of the almighty Father, from whom the Spirit comes, and to whom the Son goes.
The new Man therefore ascended into heaven, that through His grace the Spirit might deign to come to the earth. The Holy Spirit came from heaven, that He might announce to mortals that Christ reigns with the Father. For who else could open the divine secret to those dwelling on earth, unless a partaker of the Divinity had come from heaven? So then it was read, as you have heard: 'And when the days of Pentecost were being fulfilled, they were all with one accord together in the same place' (Acts 2). And a little after he says: 'They were all filled with the Holy Spirit, and began to speak with various tongues, as the Spirit gave them to utter.' The apostles therefore were of one accord, and they were filled with the Holy Spirit.
He comes to those who are of one mind, He visits the concordant, He rewards the peacemakers, and He willingly filled the hearts of the venerable apostles, whose breasts Christ the author and master already inhabited: 'And the Holy Spirit sat upon each one of them,' as we have heard (Acts 2). Observe, dearly beloved, that the breast of the peaceful is the seat of God, as blessed David says: 'And His place is made in peace.' Nor is it to be doubted that the apostles kept toward one another the grace of unanimity, to whom Christ, about to pass to the Father, had foretold: 'By this shall all know that you are My disciples, if you have love one toward another' (John 13). And again: 'My peace I give to you, My peace I leave with you.'
It is no wonder, therefore, if in the breasts of the apostles the mutual love and peace of Christ delighted the Holy Spirit. We read also in the Gospel that the Savior said to His disciples: 'I will ask the Father, and He will give you another Paraclete' (John 14). And again He says: 'For if I go not away, the Paraclete will not come to you; but if I go away, I will send Him to you.' Who, then, will be able with impunity not to believe either that the Holy Spirit is God, who was foretold and came through the Son of God, or that Christ is Lord, whose saving promise the everlasting Father fulfilled? Great, brethren, and incomprehensible is this mystery, that from earth to heaven goes the Man who sends God to us from heaven to the earth.
And truly this is the peace and harmony of the Deity, that both Christ was born while the Spirit announced it, and the Spirit descended while Christ promised it. They speak to one another in turn, they send one another in turn, they obey one another in turn, because in them there is nothing of diverse willing or ability, and they ever accomplish with the Father one mystery for the eternity of mortals. 'It is expedient for you,' He says, 'that I go' (John 16). How marvelous is this gift of our salvation! that just as it was expedient for you that Christ should come from heaven, so it was expedient that He should also return. It was expedient that He come, to give His blood for us; it was expedient likewise that He return, to bestow His Spirit upon us.
They were filled, therefore, as it was read, with the Holy Spirit, and began to speak with various tongues, as the Spirit gave them to utter (Acts 2). This variety of tongues announces the unity of the Divinity. Diverse indeed and manifold was the speech that came forth from each, but One spoke in all. A Hebrew sounds forth a tongue he had not before learned, that a Gentile might be able to hear the faith which he did not know. Nor is it any wonder, dearly beloved, if Christ through the Holy Spirit gave to His apostles knowledge of tongues—He who could restore walking to the lame, eyes to the blind, and speech to the dumb. And therefore, brethren, let us not doubt concerning these things, but with all devotion believe, because both all things are possible to God, and it was necessary that new miracles of speech should confirm the new faith.