At the Pentecost Octave, the Church celebrates an end and a beginning. It is the close of the Paschal cycle, which celebrates the close of the Old Covenant. This is the beginning of the Time after Pentecost, celebrating the birth of the Church under the New Covenant not of the letter, but of the Spirit (II Cor. 3:6). From Advent to Christmas to Lent, Easter, and the Ascension, our Lord accomplished the work of establishing the New Kingdom of God.
Each one of them brought with it a special grace, which produced in our souls the reality signified by the Rites of the Liturgy. At Christmas, Christ was born within us; at Passiontide, He passed on and into us his sufferings and atonements; at Easter, he communicated to us his glorious, his untrammelled life; in his Ascension, he drew us after him, and this even to heaven’s summit; in a word, as the Apostle expresses all this working, Christ was formed in us (Gal. 4:19).
But in order to give solidity and permanence to the image of Christ formed within us, it was necessary that the Holy Ghost should come, that so he might increase our light, and enkindle a fire within us that should never be quenched. This divine Paraclete came down from heaven; he gave himself to us; he wishes to take up his abode within us, and take our life of regeneration entirely into his own hands. Now, it is during the period called, by the Liturgy, The Time after Pentecost, that there is signified and expressed this regenerated life, which is to be spent on the model of Christ’s, and under the direction of his Spirit. 
We may recall here the words of the Epistle at the Ascension: The former treatise I made, O Theophilus, of all things which Jesus began to do and to teach (Acts 1:1). From Advent to Pentecost, our Lord’s work was only beginning. And again His Majesty has declared: Amen, amen I say to you, he that believeth in me, the works that I do, he also shall do; and greater than these shall he do, because I go to the Father (Jn. 14:12). Therefore we see in Pentecost and thereafter the work of Jesus Christ continued in His Body, the Church. Just as our Lord was incarnate of the Holy Spirit, so too we sinners, like Mary Immaculate, say “fiat”: let it be done to me according to thy word (Lk. 1:38) In this way, too, Christ is formed in us, in order to “give solidity and permanence to the image of Christ within us” by the Holy Spirit.
We may speak, then, of the Season of Advent and Christmas of a season of the virtue of hope — first, of our Lord’s coming in the flesh (and at the end of time), then in His infancy, the hope of His salvation to the world. This closes the season with Simeon’s words of hope in the last words of the Gospel at Candlemas: A light to the revelation of the Gentiles, and the glory of thy people Israel (Lk. 2:32). This phrase points to Pentecost, as we shall see.
Through Lent, Passiontide, Paschaltide, and the Ascension, we recite the most important events in our creed, thus we see an emphasis on faith. This is the foundation of our hope for eternal salvation, since our King accomplished the work of despoiling the prince of darkness in order to establish his rule. This work is the object of our faith. For if thou confess with thy mouth the Lord Jesus, and believe in thy heart that God hath raised him up from the dead, thou shalt be saved. For, with the heart, we believe unto justice; but, with the mouth, confession is made unto salvation (Rom. 10:9–10). This faith must believe unto justice in order to be a saving faith; as His Majesty said, he that believeth in me, the works that I do, he also shall do. We have been strengthened in our foundation, and now we must work.
Thus we find in Pentecost the longest season of the year, named for the Gift of God, the Holy Ghost. St. Thomas says charity is “the proper name of the Holy Ghost” (ST I q37 a1). Therefore, having laid the necessary foundation in hope and faith, we come to the season of the greatest of these: charity (I Cor. 13:13). Guéranger says further in the passage quoted above that following Christmas and Lent, After Pentecost is “a season when holy Church reaps the fruits of that holiness and doctrine, which those ineffable mysteries have already produced” and that it is “the season that is under the direction of the Holy Ghost.” This direction is so that the faith and hope engendered may not be sterile in the Christian soul, but may produce charity. These are the greater works of Jesus Christ. Neither circumcision availeth any thing, nor uncircumcision: but faith that worketh by charity (Gal. 5:6), and again, if I should have all faith, so that I could remove mountains, and have not charity, I am nothing (I Cor. 13:2).
It is by this charity of the Holy Ghost that Jesus Christ becomes the light of revelation to the Gentiles. Our Lord Himself closed His ministry at Jerusalem, having only occasional contact with the Gentile world. But His Majesty said, I have yet many things to say to you: but you cannot bear them now. But when he, the Spirit of truth, is come, he will teach you all truth (Jn. 16:12). There were indeed many things our Lord knew could not be borne by the apostles at that time. But the Holy Spirit, who is Charity, enkindled at Pentecost that “fire within us that should never be quenched,” as Guéranger puts it. This fire of charity burned for souls, first among the Jews and then among the Gentiles. It was this fire of charity that made the Jewish Christians not scorn the heathen converts at Antioch, but marvel at the mercy of God: [h]aving heard these things, they held their peace, and glorified God, saying: God then hath also to the Gentiles given repentance unto life (Acts 11:18).
It is not the earthly kingdom of Israel that is established by the Holy Ghost. He establishes the reign of Christ the King in the Kingdom of God. As Augustine says, “two cities have been formed by two loves: the earthly by the love of self, even to the contempt of God; the heavenly by the love of God, even to the contempt of self.” Thus it is in the Holy Ghost, who is Charity, that the reign of Christ is made effective. An early Greek variant in the text of the Our Father according to St. Luke replaces thy kingdom come with thy Spirit come upon us and sanctify us. And again the King says, [T]he kingdom of God is within you (Lk. 17:21), and again if I by the Spirit of God cast out devils, then is the kingdom of God come upon you (Mt. 22:28).
Since this Kingdom is founded on Charity Himself, not on force of arms like the Muhammadan false kingdom, it is truly within you. It is when the soul freely accepts the Gospel that the King drives out the devils from her, that He may reign by the Spirit of God. But, as I discussed during Ascensiontide, if this Kingdom of God is just in our hearts, then we have accepted a Gnostic dualism and abandoned Christ crucified in the flesh.
Rather, the Kingdom of God is a fundamentally political loyalty. He is the King of Kings. The heathen or Jewish convert forsakes his former blasphemy — we have no king but Caesar (Jn. 19:15) — and by the Holy Ghost says Jesus Christ is Lord (I Cor. 12:3). Caesar belongs to his true Lord, and he also must be made subject to His awful majesty, our great God and savior, Jesus Christ (Tit. 2:13). Give to God what is God’s (Mk. 12:17) — and our King has taken possession of His universal Kingdom by the Holy Ghost. Therefore, give to Caesar what is Caesar’s, but give Caesar himself to the One to whom he belongs.
Our King came to set fire upon the earth (Lk. 12:49), and this is the fire of charity in the Holy Ghost, by whom the nations are made subject freely to the true King, the Gospel of His reign is announced, and souls are freed from slavery to the empire of death (Heb. 2:15). Therefore, say ye among the Gentiles, the Lord hath reigned. For he hath corrected the world, which shall not be moved: he will judge the people with justice (Ps. 95:10). For all the gods of the Gentiles are devils: but the Lord made the heavens (Ps. 95:5). Repent and bring ye to the Lord, O ye kindreds of the Gentiles, bring ye to the Lord glory and honour… Let all the earth be moved at his presence (Ps. 95:8–9). May all the kings of the earth give glory to thee (Ps. 137:4). And may the Church say: We give thee thanks, O Lord God Almighty, who art, and who wast, and who art to come: because thou hast taken to thee thy great power, and thou hast reigned (Apoc. 11:17). Not with an army, nor by might, but by my spirit, saith the Lord of hosts (Zech. 4:6).
 Liturgical Year, Volume X, Chapter 2: The Mystery of the Time After Pentecost
 Nestle-Aland, Novum Testamentum Graece et Latine (Deutsche Bibelgesellschaft, 1986), 195
Timothy Flanders is the editor of OnePeterFive. He is the author of City of God versus City of Man: The Battles of the Church from Antiquity to the Present and Introduction to the Holy Bible for Traditional Catholics. His writings have appeared at OnePeterFive and Crisis, as well as in Catholic Family News. In 2019 he founded The Meaning of Catholic, a lay apostolate dedicated to uniting Catholics against the enemies of Holy Church. He holds a degree in classical languages from Grand Valley State University and has done graduate work with the Catholic University of Ukraine. He lives in Michigan with his wife and five children.