Holy Leaven in the context of "Death of Jesus"

The Words of Institution, also called the Words of Consecration, are words echoing those of Jesus himself at his Last Supper that, when consecrating bread and wine, Christian eucharistic liturgies include in a narrative of that event. Eucharistic scholars sometimes refer to them simply as the verba (Latin for "words").

Almost all existing ancient Christian churches explicitly include the Words of Institution in their eucharistic celebrations and consider them necessary for the validity of the sacrament. This is the practice of the Catholic Church's Latin liturgical rites and Eastern Catholic liturgies, the Eastern Orthodox Church, and all the Oriental Orthodox Churches, including the Armenian, the Coptic, the Ethiopian and the Malankara, as well as the Anglican Communion, Lutheran churches, Methodist churches, and Reformed churches. The only ancient eucharistic ritual still in use that does not explicitly contain the Words of Institution is the Holy Qurbana of Addai and Mari, used for part of the year by the Church of the East denominations, namely Assyrian Church of the East, Ancient Church of the East, and the Chaldean Syrian Church, due to their tradition of using the Holy Leaven. The Chaldean Catholic Church and the Syro-Malabar Church, two of the Eastern Catholic Churches, use the same Anaphora, but insert in it the Words of Institution. However, groups authorized by the Catholic Church to review the Qurbana recognized the validity of this eucharistic celebration in its original form, without explicit mention of the Words of Institution, saying that "the words of Eucharistic Institution are indeed present in the Anaphora of Addai and Mari, not in a coherent narrative way and ad litteram, but rather in a dispersed euchological way, that is, integrated in successive prayers of thanksgiving, praise and intercession."