The Pater (or Lord's Prayer) was the favourite Cathar prayer - arguably their only prayer.
It is, after all the only one sanctioned by the New Testament. 

The Cathar Pater (from the «Cathar Ritual»)
Pater noster qui es in celis, sanctificetur nomen tuum; adveniat regnum tuum.
Fiat voluntas tua sicut in celo et in terra.
Panem nostrum supersubstancialem da nobis hodie.
Et dimitte nobis debita nostra sicut et nos dimittimus debitoribus nostris.
 Et ne nos inducas in temptationem sed libera nos a malo.
Quoniam tuum est regnum et virtus et gloria in secula.
Amen.

 "Our father, which art in Heaven, Hallowed be thy name. Thy kingdom come, Thy will be done on Earth as it is in Heaven. Give us this day our supplementary bread, And remit our debts as we forgive our debtors. And keep us from temptation and free us from evil. Thine is the kingdom, the power and glory for ever and ever. Amen."