The urim (and its companion thummim) were sacred objects kept in the breastplate of judgment worn by the high priest (Exodus 28:30). Their exact form is unknown — possibly stones, lots, or gems — but their function was to provide a yes/no answer from God on matters of national or legal importance. When David asked the Lord whether to pursue the Amalekites, the priest used the urim. When Saul was rejected as king, the urim went silent (1 Samuel 28:6). After the return from exile, certain priestly claims were deferred "until there was a priest who could consult with the urim and thummim" (Ezra 2:63) — suggesting the object itself was lost. In the New Covenant, we have something greater: the indwelling Spirit of God guiding His people directly through His Word.
Exodus 28:30 — "And you shall put in the breastplate of judgment the Urim and the Thummim, and they shall be over Aaron's heart when he goes in before the LORD."
Numbers 27:21 — "He shall stand before Eleazar the priest, who shall inquire before the LORD for him by the judgment of the Urim."
1 Samuel 28:6 — "And when Saul inquired of the LORD, the LORD did not answer him, either by dreams or by Urim or by the prophets."
Ezra 2:63 — "Till a priest could consult with the Urim and Thummim."
H224 — אוּרִים (urim) — lights; the sacred lot-stones used by the high priest
H224 — אוּרִים (urim) — lights; the sacred lot-stones used by the high priest
H8550 — תֻּמִּים (thummim) — perfections, completenesses; companion to the urim