From Isaiah's Vision to Sunday Liturgy

The seraphim's threefold acclamation in Isaiah six outgrew its original setting almost immediately within later religious history. Jewish liturgy incorporated the words into the Kedushah, recited during the repetition of the Amidah prayer, treating the congregation's own recitation as a participation in the same praise the seraphim offer around the throne. Christian liturgy took up the same threefold formula independently as the Sanctus, sung or recited within the eucharistic prayer in traditions ranging from Roman Catholic to Eastern Orthodox to many Protestant churches, and the Greek Orthodox Trisagion, thrice holy, draws its name directly from this same triple repetition, though scholars distinguish the Trisagion as a related but separately developed liturgical text rather than a simple quotation. The seraphim themselves, described nowhere else in the Hebrew Bible in comparable detail, became a fixed category within later angelology largely on the strength of this one vision, illustrating how a single narrated scene can generate both an enduring visual type of being and a phrase repeated in worship across two religious traditions that otherwise read the surrounding chapters of Isaiah very differently from one another.