RATIONALE (HOLY SCRIPTURE). — Name given by the Vulgate (*rationale*) to the most sacred part of the high priest’s Hebrew vestments, which he wore on his chest (hence also called the “breastplate”) (*peristērion* in the Septuagint, Ex. 28:4) when entering the sanctuary. A detailed description is provided in Ex. 28:15–30 (cf. Ecclus. 45:10–11), which highlights its symbolic significance.
It consisted of a square piece of fabric folded into a pouch (a kind of bag) made of richly woven material in four colors and gold threads, similar to the *ephod* (q.v.), to which it was attached at the top by golden chains and fastened to the belt by two violet cords. On it were set, in four rows of three stones each, twelve precious stones of different kinds, each engraved with the names of the twelve tribes of Israel in gold. Thus, the high priest, in the most solemn act of his duties, carried “the names of the sons of Israel upon his heart... as a continual memorial before Yahweh” (Ex. 28:29). But the greatest prerogative of the *rationale* was to contain the *’urim* and *tummim* (q.v.), “light and perfection,” from which the high priest drew the responses of Yahweh in important circumstances. For this purpose, it is called in the original Hebrew *hōšen hammîpāt* (or simply *hōšen*, of uncertain etymology, perhaps equivalent to “pouch” or “ornament”), meaning “pouch of divine decisions” (λογεῖον τῶν χρόσεων, “oracle of judgments”; Vulgate *rationale iudicii*; Symmachus δόξον, “pouch”; Flavius Josephus and other Greek versions simply λόγιον, “oracle”).
The *rationale* seems to be of Egyptian origin: indeed, various figures from ancient Egypt wear a kind of trapezoidal or square ornament hanging from the neck over the chest (notable is the one found on the mummy of Queen A’ah-hōpet, mother of Amosis I, founder of the 18th Dynasty, 1580–1558 B.C.; it is in the form of a finely crafted temple with symbols, figures, and precious stones set in mosaic).