Sermon LXXV: On Pentecost I
By Pope St. Leo I (AD 390-461)
As therefore we abhor the Arians, who maintain a difference between the Father and the Son, so also we abhor the Macedonians, who, although they ascribe equality to the Father and the Son, yet think the Holy Ghost to be of a lower nature, not considering that they thus fall into that blasphemy, which is not to be forgiven either in the present age or in the judgment to come, as the Lord says: "whosoever shall have spoken a word against the Son of Man, it shall be forgiven him, but he that shall have spoken against the Holy Ghost, it shall not be forgiven him either in this age or in the age to come." And so to persist in this impiety is unpardonable, because it cuts him off from Him, by Whom he could confess: nor will he ever attain to healing pardon, who has no Advocate to plead for him. For from Him comes the invocation of the Father, from Him come the tears of penitents, from Him come the groans of suppliants, and "no one can call Jesus the Lord save in the Holy Ghost," Whose Omnipotence as equal and Whose Godhead as one, with the Father and the Son, the Apostle most clearly proclaims, saying, "there are divisions of graces but the same Spirit; and the divisions of ministrations but the same Lord; and there are divisions of operations but the same God, Who worketh all things in all."
V. The Spirit's Work is Still Continued in The Church
By these and other numberless proofs, dearly-beloved, with which the authority of the Divine utterances is ablaze, let us with one mind be incited to pay reverence to Whitsuntide, exulting in honour of the Holy Ghost, through Whom the whole catholic Church is sanctified, and every rational soul quickened; Who is the Inspirer of the Faith, the Teacher of Knowledge, the Fount of Love, the Seal of Chastity, and the Cause of all Power. Let the minds of the faithful rejoice, that throughout the world One God, Father, Son, and Holy Ghost, is praised by the confession of all tongues, and that that sign of His Presence, which appeared in the likeness of fire, is still perpetuated in His work and gift. For the Spirit of Truth Himself makes the house of His glory shine with the brightness of His light, and will have nothing dark nor lukewarm in His temple. And it is through His aid and teaching also that the purification of fasts and alms has been established among us. For this venerable day is followed by a most wholesome practice, which all the saints have ever found most profitable to them, and to the diligent observance of which we exhort you with a shepherd's care, to the end that if any blemish has been contracted in the days just passed through heedless negligence, it may be atoned for by the discipline of fasting and corrected by pious devotion. On Wednesday and Friday, therefore, let us fast, and on Saturday for this very purpose keep vigil with accustomed devotion, through Jesus Christ our Lord, Who with the Father and the Holy Ghost lives and reigns for ever and ever. Amen.
This sermon was delivered on the Feast of Pentecost. Pentecost is the celebration of the descent of the Holy Spirit upon the Apostles in the Book of Acts. It is the birthday of the Church. Translation of sermon from : Vol. XII.