BARUKH (Heb. בָּרוּךְ), initial word of the *berakhah pattern of prayer. Barukh is conventionally translated "blessed," but the etymology is disputed. The root (ברך) seems to have meant originally "bend (or fall) upon the knees (berekh = knee)" in prayerful obeisance (Ps. 95:6; Isa. 45:23). Cassuto maintains, however, that it meant originally "bestow a gift" (Gen. 24:1, 35; 33:11, et al.). Barukh is a homonym expressing a reciprocal relationship: man can address God as barukh by expressing feelings of thanksgiving, reverence, love, and praise, while he is barukh by God who bestows His material and spiritual gifts. The person upon whom the divine blessing rests is called berukh Adonai, "blessed of the Lord" (Gen. 24:31, 26:29). Barukh Adonai, in the sense of man blessing God, occurs 24 times in the Bible.
The pattern barukh Attah Adonai ("blessed art Thou, Lord") occurs only twice in biblical literature (Ps. 119:12; i Chron. 29:10). This second person form attained currency no earlier than about the fourth century b.c.e. There is, however, no substantive difference between the second and third person forms. As applied to God "blessed" is identical with "praised" and the formula of blessing viz. benediction is, in fact, one of praise.
The prototype of the classical berakhah is to be found in the biblical formula, barukh Adonai… asher… (e.g., Gen. 24:27; Ex. 18:10), in which he who has experienced the marvelous or miraculous expresses adoration and awe. This pattern persisted for centuries and was eventually adapted for liturgical use as the Jew's response to "the miracles of every day." But the insertion of the pronoun Attah ("Thou") was slow in gaining exclusive acceptance. Some of the variant forms of the berakhah persisted until the third century c.e. when the standard pattern was fully established (Ber. 40b). In third-century Babylonia, Rav and Samuel were still debating whether Attah was required in the formula (tj, Ber. 9:1, 12d). Rav's pattern, barukh Attah Adonai, became the standard opening phrase; but the old biblical formula in which barukh (Attah) Adonai was followed by the characteristic phrase, asher ("who," i.e., "performed some beneficent act") remained in use. This juxtaposition of direct address to God and a sequel in the third person created a syntactical paradox which has exercised commentators and theologians down to the present. Many commentators explain the juxtaposition of second and third person homiletically as indicating both God's nearness and transcendence. The second person address is referred to in traditional sources as nigleh ("revealed") and the third person as nistar ("hidden").
Blank, in: huca, 32 (1961), 87–90; Bamberger, in: Judaism, 5 (1956), 167–8; M. Kadushin, The Rabbinic Mind (19652), 266–70 (theological aspect); J. Heinemann, Ha-Tefillah bi-Tekufat ha-Tanna'im re-ha-Amora'im (19662), 29–77 (textual criticism).
"Barukh." Encyclopaedia Judaica. . Encyclopedia.com. (December 14, 2018). https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/barukh
"Barukh." Encyclopaedia Judaica. . Retrieved December 14, 2018 from Encyclopedia.com: https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/barukh