Shavua Tov. The אורים ותומים that were worn on the breastplate of the Kohein Gadol, were magical in nature.
The אורים refers to how the breastplate, the חושן, lit up when an inquiry was made by the כהן גדול. The תומים, referred to the ability of the High Priest to unscramble the message. There were a total of seventy two letters on the חושן, which included the names of the twelve tribes as well as אברהם, יצחק, ויעקב.
At the very beginning of the Book of Shoftim, the following question is asked of Hashem. “Who will go forth to do battle with the כנעני?” The answer given was, ״יהודה ועלה״.
The commentators explain that the אורים ותומים were asked this question and the name, “יהודה” lit up as well as the four letters that spell, ״יעלה״. The people then knew that Hashem wanted the Tribe of Yehuda to lead the battle against the כנעני.
The אורים ותומים were magical, indeed.