Kedushah (Hebrew, holiness) in Judaism, this term means set apart through holiness. The biblical commandment, “you shall be holy, for I the Lord your God am holy” (Leviticus 19:2) has consistently been understood by rabbis as requiring that the Jew must be a people “set apart.” God’s fearful holiness is associated with his moral purity (Psalms 24:3-4) which will manifest itself in divine judgment (Isaiah 1:4-9) and in mercy (Isaiah 29:19-21). It is something to be feared as well as adored, and, by serving God, the individual can become sanctified. The ultimate hope is that not only the Jewish nation, but the whole universe will be filled with divine glory, kavod. The prophet Zechariah looked forward to a time when even bells on horses would be inscribed with “Holy to the Lord” (Zechariah 14:20-21). In rabbinic literature, holiness is of the essence of God (“The Holy One, Blessed be He”). Israel can only share in God’s holiness through the performance of the mizvot (sing, mitzvah) (Blessed are you, Lord God…who has sanctified us by your commandments). This separates the Jewish people from the nations, and as Abraham b. Hiyya put it: “The people of Israel is holy, because it separated itself from worldly pursuits, and turned to the notion of God.” More specifically, the kedushah is applied to parts of the liturgy, especially the doxologies based on Isaiah 6:3 and Ezekiel 3:12 which echo the praise of the angels. A.G.H.
Bowker, John, The Oxford Dictionary of World Religions, New York, Oxford University Press, 1997, p. 540