What about the prayer from the Boondock Saints? Not exactly an incantation, but iconic.
Quote:And Shepherds we shall be
For thee, my Lord, for thee.
Power hath descended forth from Thy hand
Our feet may swiftly carry out Thy commands.
So we shall flow a river forth to Thee
And teeming with souls shall it ever be.
In Nomeni Patri Et Fili Spiritus Sancti.