Polyeleos

The Polyeleos (from polys, many, and eleos, mercy — 'many mercies') is the solemn chanting of Psalms 134-135 at Orthros on feast days and commemorations of important saints. The refrain 'for his mercy endures forever' is repeated after each verse, producing an extended doxological meditation on divine mercy in the context of creation and salvation history. The Polyeleos is one of the liturgical indicators that a feast is being celebrated: its presence distinguishes a feast day Orthros from a weekday one.