Parshas Tetzaveh 5777

What is the Urim veTumim?

The Torah writes (Exodus 28:30):

Inside the breastpiece of decision you shall place the Urim and Thummim, so that they are over Aaron’s heart when he comes before the LORD. Thus Aaron shall carry the instrument of decision for the Israelites over his heart before the LORD at all times.

Rashi (ibid) explains:

This was an inscription of the Proper Name of God which was placed between the folds (i. e. the two pieces forming the front and back) of the breast-plate through which it (the breast-plate) made its statements clear (lit., illuminated its words; מאיר from אור, light, this being an allusion to the אורים) and its promises true (מתמם from the root תמם, an allusion to תמים) (Yoma 73b).

The Rashbam (ibid) explains the purpose:

the function was somewhat similar to that of oracles employed by the priests of idolatrous cults. If those had any value at all, -and we may assume that at least their worshippers had concluded that they did, -how much more influential would these urim vetumim in the sacred garments of the High Priest be in order to elicit answers to questions posed to G’d, seeing that the means employed were holy and sanctioned by G’d Himself?

Rabbeinu Bachya explains that these were not made by human hands:

It is mentioned with the letter "ה" as it was known before but we do not see it being cited anywhere until now, for it is not mentioned with the other vessels in the work of the artisans to say "and they made the Urim and Tumim" like it says by other vessels. This is testimony that this was not made by a human artisan but directly by Heaven, and this is why it is mentioned with this letter like we find earlier [Genesis 3] regarding the angels, all this is mentioned by the Ramban.

Ibn Ezra as cited by the Tur disagrees:

Nachmanides writes that Ibn Ezra,in an effort to be very astute, wrote that the Urim and Tumim were something constructed by human hands, by artisans. (compare Leviticus 8:8 where Moses is described as placing the Urim and the Tumim inside the breastplate after Aaron already wore the breast plate). He clearly thought that these Urim and Tumim were something man made of silver and/or gold. He appears to have thought that these mysterious inserts were similar to what the astrologers use in order to understand communications from their zodiac signs

The Tur also mentions other "Turim":

It is quite possible that these names of G’d which Moses wrote on the parchment which he inserted in the folds of the breast plate, were known as such to the elite of the Jewish people at the time, and that this would explain the use of the definitive article used here, i.e. האורים, התומים, something which is never used unless the subject is a known quantity, a phenomenon that at least some people are familiar with. This may also explain why David possessed an ephod comparable to that which Moses had in his time, and why we read that in Nov the city of priests (whom King Shaul murdered) there were 85 priests wearing such a type of ephod. (compare Samuel I 22:18) These priests were all trained by prophets, and possibly they used their ephods to address inquiries to G’d on certain occasions.

(see also here and here)