The Palestinian Talmud on the Kedushah

This passage contains an early reference to what became known as the Kedushah, an embellished dramatic recitation of two scriptural verses that represent the angelic praise of God as heard by the prophets Isaiah and Ezekiel in their consecration visions: Holy! Holy! Holy! Adonai of hosts! His glory fills all the earth! (Isaiah 6:3) and Blessed be the glory of Adonai from his place! (Ezekiel 3:12). This passage attests that some version of the Kedushah was already recited responsively in the midst of the Tefillah by the third century CE and that it included a reference to the ’ofanim (animate wheels) from Ezekiel’s vision. See also The Tosefta on the Kedushah and A Version of the Kedushah from the Land of Israel.