At the right and left of the breastplate were two large stones of great brilliancy. These were known as the Urim and Thummim. By them the will of God was made known through the high priest. When questions were brought for decision before the Lord, a halo of light encircling the precious stone at the right was a token of the divine consent or approval, while a cloud shadowing the stone at the left was an evidence of denial or disapprobation.

På brystskjoldets højre og venstre side var der to store funklende stene. Disse kaldtes Urim og Tummim. Ved hjælp af dem meddeltes Guds vilje gennem ypperstepræsten. Når der blev forelagt Herren et spørgsmål til afgørelse, var en stråleglans omkring ædelstenen på højre side et tegn på Guds tilladelse eller anerkendelse, mens en skygge omkring stenen på venstre side var et bevis på nægtelse eller misbilligelse.