Oracles are the divine revelations given to Gods people. Gods method of communicating these oracles varied from dreams and visions (Num. 12:6-8), to wisdom (Prov. 30:1), and even the Urim and Thummim (Num. 27:21; 1 Sam. 14:3-37).
The Urim and Thummim were placed in the breastplate of the high priest (Ex. 28:30) and were used as a means of communication with God. They mean “light” and “perfection”. Unfortunately, they are not described anywhere in the Bible. Some theories maintain that they were twelve stones that made up part of the high priests garments. The process of the communication with God is not given either.