QEDHŪŠĀH. — Trisagion, a liturgical composition inserted into the morning prayer at the time of the repetition of the Šēmōneh 'ešrēh (v.) by the religious official.
It derives its origins from Is. 6:3 and, in its fuller form, also contains Ezek. 3:12b; Ps. 146:10; Deut. 6:4; Num. 15:41c. In its distant and obscure origins, the Q. was recited only on feast days; in time, also on weekdays and after the public sacred readings. The Q. exerted a notable influence on the Christian liturgy.
BIBL.: I. Elbogen, Gesch. des jüd. Gottesdienstes, 2nd ed., Francoforte s. M. 1924, pp. 61–67, 79; M. E. Jernensky, Keduscha, in Enc. Iud., IX, cols. 1118–23. On Q. and trisagion cf. A. Baumstark, in Jahrbuch für Liturgiewissenschaft, 3 (1923), p. 18 ff.; E. Peterson, Theologische Traktate, Monaco 1951, pp. 333, 344 ff., 385. Eugenio Zolli