The Breastplate and Urim & Thummim

Breastplate of judgment and tribal stones

The breastplate (Hebrew: choshen, possibly from a root meaning 'to contain' or 'to sparkle') was the most elaborate and theologically significant of the high priest's eight vestments. Exodus 28:15-30 describes it in careful detail as 'the breastplate of judgment' (choshen ha-mishpat), indicating its primary function: it was the device through which God's judicial decisions were communicated to Israel. The twelve stones symbolized Israel's tribal identity before God; the Urim and Thummim hidden inside were the oracular mechanism.

The Twelve Stones: The breastplate was square - 'a span square' (approximately 22 cm per side) - folded double to create a pouch. Four rows of three stones were set in gold filigree on the outer face, each stone engraved with one tribal name. The stones in Exodus 28:17-20 are: row 1 - odem (ruby/carnelian), pitdah (topaz/peridot), bareqet (emerald/green feldspar); row 2 - nophek (turquoise/carbuncle), sappir (sapphire/lapis lazuli), yahalom (diamond/moonstone); row 3 - leshem (jacinth/amber), shevo (agate), achlamah (amethyst); row 4 - tarshish (chrysolite/beryl), shoham (onyx), yashpeh (jasper). The identification of these stones with modern gem names is highly uncertain because the Hebrew terms do not map directly to modern mineralogical categories, and ancient stone names were sometimes applied differently than today.

Bearing all Israel on heart and shoulder

The Symbolic Weight of the Tribal Names: The theological significance of carrying all twelve tribal names on the priest's chest is spelled out explicitly: 'Whenever Aaron enters the Holy Place, he will bear the names of the sons of Israel over his heart on the breastpiece of decision as a continuing memorial before the LORD' (Exod 28:29). This 'bearing' language echoes the language of intercession - the high priest brought Israel's full identity into the divine presence. The names were also on the two onyx stones on the ephod's shoulder straps (six names per stone, Exod 28:9-12) - Israel was borne both on the priest's shoulders (power, authority) and on his heart (love, intercession). Paul's language in Philippians 1:7 - 'I have you in my heart' - may consciously echo this imagery.

Urim and Thummim: theories of operation

The Urim and Thummim: Exodus 28:30 commands: 'Also put the Urim and the Thummim in the breastpiece, so they may be over Aaron's heart whenever he enters the presence of the LORD. Thus Aaron will always bear the means of making decisions for the Israelites over his heart before the LORD.' The Urim and Thummim (urim ve-thummim) are among the most enigmatic objects in the entire Hebrew Bible. The terms are not defined, their physical form is never described, and their mechanism of operation is never explained. The names may mean 'lights and perfections,' 'illumination and truth,' or 'cursed and blameless' - each suggests a binary oracular function (yes/no, guilty/innocent, this tribe/that tribe).

How They May Have Worked: Several theories attempt to reconstruct the Urim and Thummim's oracular mechanism. The simplest and most widely accepted theory holds that they were two small stones or objects (perhaps inscribed) that could be drawn from or shaken within the breastplate pouch - one indicating 'yes' (or one option), one indicating 'no' (or another option). This would make them comparable to the sacred lots (goralot) used elsewhere in Israelite decision-making (Lev 16:8 - lots over the two goats; Josh 7:16-18 - lots to identify Achan; Acts 1:26 - lots to choose Matthias). The lot was not understood as random but as guided by God: 'The lot is cast into the lap, but its every decision is from the LORD' (Prov 16:33).

A more elaborate theory proposes that the twelve stones on the breastplate itself lit up selectively to spell out letters forming a divine response - a theory found in the Babylonian Talmud (Yoma 73b: 'the letters would spring forward or raise themselves') and reflected in some modern fiction (Tolkien's palantiri have been compared). But no biblical text describes this mechanism, and it is generally regarded as later legendary elaboration.

Historical usage and silence after the exile

Historical Usage: The Urim and Thummim are consulted for significant national questions throughout the early biblical period. Numbers 27:21 stipulates that Joshua should 'stand before Eleazar the priest, who will obtain decisions for him by inquiring of the Urim before the LORD.' 1 Samuel 14:41 (in the LXX) records Saul asking God 'Give Thummim' or 'Give Urim' in seeking to identify who violated the oath - the LXX preserves a binary query structure that the Hebrew MT omits. 1 Samuel 23:9-12 and 30:7-8 show David regularly consulting the ephod (and presumably the Urim and Thummim) for military decisions. The failure of this consultation is noted in 1 Samuel 28:6: 'he inquired of the LORD, but the LORD did not answer him by dreams or Urim or prophets' - the silence of the Urim is a sign of divine rejection.

Prophecy replaces priestly oracle

Disappearance After the Exile: After the Babylonian exile, the Urim and Thummim disappear from Israelite practice. Ezra 2:63 (= Neh 7:65) records that the post-exilic community could not verify the priestly lineage of certain families and therefore excluded them from the priesthood 'until a priest could consult the Urim and Thummim' - clearly implying that no such consultation was currently possible. This reference acknowledges both the institution's original authority and its current absence. The later priestly traditions universally acknowledge that the Urim and Thummim were not available in the Second Temple. Josephus (Antiquities 3.218) says the stones on the breastplate shone during sacrifice to indicate divine favor, and that this ceased 'some two hundred years' before his writing - approximately the early Hasmonean period.

Prophecy as Replacement: When the Urim and Thummim ceased, prophetic inquiry became the primary mechanism of divine communication. The canonical prophets (Isaiah, Jeremiah, Ezekiel, and the Twelve) represent the blossoming of a prophetic tradition that served the function previously filled by oracular consultation. After the prophetic period also ended (in Jewish tradition, with Malachi), the rabbis acknowledged a period without direct divine communication, anticipating its renewal in the messianic age.

Scholarly Sources: Cornelis Van Dam, The Urim and Thummim: A Means of Revelation in Ancient Israel (1997), is the most comprehensive study. Jacob Milgrom, Leviticus (Anchor Bible, 1991), pp. 505-511, provides exegetical analysis. For the oracular lot parallel, see Lester Grabbe, Priests, Prophets, Diviners, Sages (1995), ch. 2. Tremper Longman III, 'Urim and Thummim' in the Dictionary of the Old Testament: Pentateuch (2003), provides a good survey of theories.

• ISBE: Urim and Thummim; Breastplate
• ABD: Urim and Thummim
• Van Dam, The Urim and Thummim (1997)
• Milgrom, Leviticus Anchor Bible (1991)
• Grabbe, Priests Prophets Diviners Sages (1995)