Why does the Torah use the word 'Milu'im'?
Rashi: Because the stones filled the settings. 1
Rashbam: They made holes in which to set the stones.
Ba'al Shem Tov: Each letter has a Miluy 2 . Together with each letter that lit up, the letters of its Miluy lit up. This enabled answers in which a letter is repeated. 3 All 22 letters appear additionally in the Miluy of others letters, just Mem appears only in its own Miluy (Mem Mem). 4
What is the significance of the four rows of stones?
Targum Yonasan: They corresponded to the four corners of the earth.
Ba'al ha'Turim: They corresponded to the four camps (Yehudah, Reuven, Efrayim and Dan) and the four mothers.
Oznayim la'Torah: The four rows corresponded to the four Imahos and the three stones to a row to the three Avos.
What purpose did the stones of the Choshen serve?
Refer to 28:15:1 - 5.
Ramban #1 (on Pasuk 35, citing Midrash Rabah): When the Kohen Gadol entered the Heichal on Yom Kipur, Hashem looked at them and remembered the merits of the Shevatim. 1
Ramban #2 (Ibid.): It can be compared to the tutor of the king's son, who wanted to come before the king to plead on behalf of his son, but who was afraid that the king's men would attack him. So what did the king do? He dressed him in his royal robes, thereby causing his men to be afraid to touch him. In the same way, Aharon had to enter the Kodesh Kodshim 2 many times on Yom Kipur) and these merits (of K'lal Yisrael) entered with - only he was unable to do so, because of the angels who were serving Hashem. 3 Therefore Hashem dressed him in the image of His royal robes. 4