The Canons of the Council in Trullo; Often Called The Quinisext Council 81Canon LXXXI.

Whereas we have heard that in some places in the hymn Trisagion there is added after "Holy and Immortal," "Who was crucified for us, have mercy upon us," and since this as being alien to piety was by the ancient and holy Fathers cast out of the hymn, as also the violent heretics who inserted these new words were cast out of the Church; we also, confirming the things which were formerly piously established by our holy Fathers, anathematize those who after this present decree allow in church this or any other addition to the most sacred hymn; but if indeed he who has transgressed is of the sacerdotal order, we command that he be deprived of his priestly dignity, but if he be a layman or monk let him be cut off.