What is a Liturgical Calendar?

   
In Scripture

In Gods Word we read about a systematic reading through the Scriptures. For example, Luke 4:14-21 provides an account of Jesus' participation in a synagogue service on a Sabbath in his hometown of Nazareth. There were two readings given during the service: the first was a continuous lectionary of the Pentateuch, the second (called the Haftara) was taken from the prophetical books.

The reading of the Pentateuch 

The reading of the Pentateuch was equally divided over a year of Sabbaths so that it would be read in its entirety throughout the course of the year (or as in some lectionaries, over a three or three-and-a-half year period). The prophetic cycle of the second reading as found in this passage from Luke was probably in its early developmental stages and was not yet fully fixed. 

The second reading from the prophetical books

The second reading was to be thematically connected to the reading of the Pentateuch or to the particular festal season that was being celebrated. Thus the second reading became a seasonal lectionary.

In the Early Centuries

The lectionary of the synagogue continued in the Christian 'synagogues'. Justinian writes, "The memoirs of the apostles or of the prophets are read as long as time permits." It appears that in the early centuries a continuous lectionary was generally used except for the fixed feast days. On those days a text fitting to the occasion was read.