Also see the Haydock Commentary provided by John Gregory: The Prophets Prove the Profits of Grace
Easter being variable, the number of Sundays from Pentecost, to the first Sunday of Advent is, of course, variable also; but there cannot be less than twenty-three, nor more than twenty-eight. The Mass for the Last Sunday: after Pentecost is always said on the Sunday preceding Advent. If there are more than twenty-four Sundays after Pentecost, the Introit, Gradual, and Communion of the twenty-third Sunday are repeated on all the remaining Sundays. But the Prayers, the Epistle and the Gospel are taken from the Masses of the Sundays omitted after the Epiphany.Go to the ORDINARY OF THE HOLY MASS THE MASS OF THE CATECHUMENSINTROIT: Jeremias 29: 11, 12,14
Our Mother, the Catholic and Roman Church, is imbued with the word of Christ, and is admirably represented by the three measures of meal, which the energy of fermentation wholly leavened and by the mustard tree, the greatest of its kind, where the birds of heaven are glad to find shelter. May the "leaven" of the doctrine of Jesus pervade and transform our souls! Jesus, our Redeemer, is God. He works wonders. The Angels of Heaven, Jews and Gentiles will be obliged to recognize His royal Divinity.
St. Paul focuses in his epistle to the Thessalonians on how the word of God produces in the hearts of Christians the wonders of faith, hope and charity. And in the Gospel, Jesus reveals to us "things hidden from the foundation of the world" with parables of the three measures of meal and of the mustard plant.
We want to thank the Friends of Our Lady of Fatima for expediting these resources of the Propers. Sources: Saint Andrew Daily Missal and the Marian Missal , 1945