Prokimenon and Alleluia
The reading of the Epistle is preceded by two verses of Psalm and followed by two others with Alleluia.
Basic Rules:
There is a Prokimenon for each Sunday according to the cycle of the Octo-Echos. The Tone of the Prokimenon designated to a specific Sunday in the cycle of the Triodion, Pentecostarion, etc. does not necessarily correspond to the Octo-Echos Tone.
The Menaion has Prokimenon and Alleluia verses for the its Feasts.
At any other time, the Prokimenon and Alleluia are at beginning of the Epistle Book and are per the following schedule: