Appendix: The Revised Common Lectionary
A lectionary is a schedule of Scripture readings arranged and intended for proclamation during worship. The Revised Common Lectionary is a three-year schedule prepared by the Consultation on Common Texts, an ecumenical consultation of liturgical scholars and denominational representatives from the United States and Canada who produce liturgical texts for use in common by North American Christian churches. The lectionary presented here is adapted from the Revised Common Lectionary, © 1992 by the Consultation on Common Texts and used with permission.
The three years (designated A, B, and C) include several Scripture readings for each Sunday: an Old Testament reading; a psalm, preferably sung, which serves as a congregational response to the Old Testament reading; a reading from one of the New Testament epistles; and, finally, a reading from one of the four gospels—Matthew in Year A, Mark in Year B, and Luke in Year C. Readings from the Gospel of John are included in all three years. Over the three years, at least one reading from each book of the Bible is included.
For the Sundays following Pentecost, there are two suggested readings from the Old Testament: one that is chosen to set up a semicontinuous set of readings through the Old Testament over several weeks, and one (listed in italics) that continues the pattern of offering Old Testament readings that are complementary to the New Testament readings. The term complementary here means that the juxtaposition of the Old Testament and New Testament readings is theologically significant in some way. However, it is important to understand that the inter-relationships among texts throughout the lectionary come in several forms: some combinations of Old Testament and New Testament readings explore contrasting themes, while others explore the same theme or image; some feature an Old Testament prophecy and its New Testament fulfillment, while others feature an Old Testament narrative that is a type or pattern echoed in a New Testament narrative or parable.
You can find the Revised Common Lectionary on pages 1058-1067 of Psalms for All Seasons.