"He shall stand before Eleazar the priest, and he shall inquire for him by the judgment of the Urim before Jehovah; at his word they shall go out, and at his word they shall come in, both he and all the sons of Israel with him, even the whole assembly" (v. 21). Exodus 28:30 speaks of putting the Urim and the Thummim in the breastplate of judgment, which was worn by the high priest. The breastplate contained twelve stones, and on each stone was written the name of one of the twelve tribes. In David Baron's book The Ancient Scriptures and the Modern Jew there is an appendix with an article on the Urim and the Thummim. According to this article, the twelve names on the breastplate included eighteen of the twenty-two letters in the Hebrew alphabet. The remaining four letters were put on a piece called the Thummim. The Hebrew word Thummim means perfecters or completers. Thus, on the breastplate with the additional piece called the Thummim, all twenty-two letters of the Hebrew alphabet could be found. These letters could be used to spell out words and sentences.
Furthermore, according to this article, the Urim was an illuminator inserted into the breastplate underneath the twelve stones. In Hebrew the word Urim means lights or illuminators. This article goes on to say that the Urim had twelve illuminators, one to illuminate each piece of stone on the breastplate. When the Urim and the Thummim were added to the breastplate, they caused it to become the breastplate of judgment.
When God brought His people into the wilderness, He spoke to them through Moses. God spoke to Moses face to face. But Joshua, Moses' successor, was to receive guidance not from God by His direct speaking in the way He spoke to Moses, but by the Urim and the Thummim on the breastplate worn by Eleazar the priest. Whenever Joshua needed guidance concerning the move of the people, he had to go to the high priest, who then received guidance from God by means of the Urim and the Thummim.
Although Joshua was made the leader, he did not have the right to receive the divine instructions directly. Instead, the high priest received God's instructions and then passed them on to Joshua, who was responsible for their execution. Whereas the high priest had the right to receive the divine instructions, he did not have the right or the authority to execute these instructions. The authority to execute the divine instructions was given to the leader, to Joshua. The people would then go out and come in according to the instructions given to the priest and executed by Joshua.
God's government among His people was a matter not of autocracy or democracy but theocracy. This divine government, this theocracy, was carried out through the coordination of the high priest, who received God's instructions, and the leader, who executed these instructions.
When Moses was leading the people in the wilderness, the divine government did not depend on the coordination of two persons, the high priest and the leader, but on one person—Moses. Moses was the leader, and he also functioned as a priest. (Aaron did not help much.) After Moses, however, the divine government depended on the two persons of the high priest and the leader. This was the case throughout the generations in the Old Testament, the only exception being the time when David served as both the leader and as the priest wearing the ephod (a vest worn over the priest's robe). When the children of Israel came back from captivity, Joshua was the high priest and Zerubbabel, a royal descendant, was the leader. The two worked together to execute the theocracy, the divine government.
Moses did as Jehovah commanded him. "He took Joshua and caused him to stand before Eleazar the priest and the whole assembly; and he laid his hands upon him, and charged him as Jehovah had spoken through Moses" (Num. 27:22-23).