The three year cycle mirrors the three year cycle of readings in Jewish tradition. One can determine the year by dividing the calendar year (remembering that it begins on the First Sunday in Advent in the previous year) by three. If it’s evenly divisible, it’s Year C. A remainder of one indicates Year A, of two, Year B. In other words, it’s as though the three year cycle began on 1 A.D. Year A plows through Matthew, Year B Mark, Year C Luke. John is sprinkled through the year, especially in Lent and Eastertide. Specials seasons, solemnities, and feasts have readings selected that fit the occasion. Otherwise, the synoptic Gospels are basically ploughed through in chapter order. The Old Testament reading in Ordinary time is selected to go with the Gospel of the Day. If Jesus quotes or refers to something in the Old Testament, that reading is the First Reading. Otherwise, it’s selected thematically. The Psalm them reflects the First Reading. Outside of feasts and special seasons, the Second Reading is semi-continuous and any relationship to the other readings is coincidental. It’s purpose is simply to expose the woshipper to more of the scripture. Notice that Eastertide uses readings from the Acts of the Apostles for the First Reading. The daily cycle is a two year cycle for the First Reading and Psalm. Year I – odd years. Year II - even years. Mainstream denominations have adopted our Lectionary with some modifications.
