A non-Catholic friend asked me how the Scriptures at Mass are selected. Who started this and when was the present system adopted?
Vatican II’s 1963 “Constitution on the Sacred Liturgy” called for a wider selection of biblical texts to be used at Mass. The current Lectionary (book of those readings) was prepared by an international committee of experts and went into use in 1970.
The cycles for Sunday readings (A, B, C) use continuous readings from the Gospels of Matthew, Mark, and Luke, respectively. The Gospel of John is used in the Easter season, some Sundays in Cycle B, and at other times.
On Sundays, the first reading is from the Old Testament and is coordinated thematically with that day’s Gospel. The second reading, a continuous one from other New Testament books, is not coordinated with that day’s Gospel and first reading.
The weekday readings have a cycle for even-numbered years and another for odd-numbered years. In fact, the Gospels are the same in each cycle, but the first reading is from the New Testament some weeks and from the Old Testament other weeks.
The Lectionary cycles present 14 percent of the Old Testament and 71 percent of the New Testament. In contrast, the readings in the 1963 Roman Missal used 1 percent of the Old Testament and 17 percent of the New Testament.
Before I graduated from grade school in 1962, the same readings were often used several times a week, repeated from those of the previous Sunday, which had the same readings for the First Sunday of Lent, etc. Few people realized this because the readings were in Latin, and they did not have their own missals to follow along in English.
This much wider selection of readings helps people better understand God’s unique self-revelation in the Bible. More of the Bible is now used at Mass and for private prayer based on the Lectionary.