The Church uses two main books to celebrate Liturgy: the Roman Missal and the Lectionary. The Roman Missal contains the prayers, rituals, and gestures used for Masses on Sundays, weekdays, and Holy Days. The Lectionary is the set of Scripture readings proclaimed at each Mass.
The Lectionary follows a three-year cycle for Sundays and Holy Days but a two-year cycle for weekdays. The Sunday cycle is determined by the gospel—A=Matthew, B=Mark, and C=Luke; the weekday cycle simply follows an odd/even split: Year I in odd years (e.g., 2021) and Year II in even years (e.g., 2022). John’s gospel is heard proclaimed in all three years, especially during Cycle B since Mark’s gospel is so brief. The intention of the three-year cycle is to hear at least one passage from each book of the Bible. In addition to determining the cycle, the gospel also decides the theme for each Mass. That theme connects the gospel to the first reading. The first reading usually comes from the Old Testament except during the Easter Season when it is taken from Acts of the Apostles. Sunday’s second reading follows the centuries-old tradition of listening to passages from a Biblical letter read over several Liturgies.
The current English translation of the Lectionary used in the United States is a modified version of the New American Bible, originally published in 1970 and revised in 1986. It is modified so that passages can make sense when taken out of context. Therefore, the Lectionary substitutes Jesus for a pronoun or adds “brothers and sisters” at the beginning of a passage from one of Paul’s letters.
In addition to a thematic approach to the gospel for each Sunday, there is a certain amount of chronology involved as well. Obviously, during Advent, the gospel readings deal with the coming of Christ and during the Easter Season they proclaim his Resurrection appearances; but notice them during that long period of Ordinary Time from Pentecost through Christ the King. The gospels more or less take us through a year of Jesus’ ministry beginning with the call of the first disciples and ending with Jesus’ warnings about the end times.
The liturgical year is circular, like the natural seasons, with Easter Sunday at its center. Easter is a movable feast—it is the first Sunday after the first full moon after the spring equinox—so all the other liturgical seasons shift accordingly. The liturgical year begins with the First Sunday of Advent, which is always the Sunday closest to the Feast of St. Andrew (November 30). Lent always begins on Ash Wednesday and lasts until sundown on Holy Thursday. The Triduum, Holy Thursday through Easter Sunday, is the shortest liturgical season at three days. If that seems confusing, remember that we follow the Jewish custom of beginning a new day at sundown the previous day. Hence, the first story of creation: “Evening came and morning followed, the first day.” “Evening came and morning followed, the second day.” etc.BACK TO LIST