What did the Torah mean when it wrote "ve'ha'Avanim Tih'yenah al Sh'mos B'nei Yisrael"?
Seforno: When the donors designate the stones, they should have in mind that the names of the tribes will be inscribed on them, that there must be twelve stones, no more and no less, and that the engraver will engrave the name of the tribe on the stone that is designated for it, and not on another stone. 1
As the Pasuk goes on to explain (See Seforno)
Why does the Torah see fit to repeat "Sh'teim-Esrei al Shemosam"?
Seforno: Refer to 28:21:1:1.
Oznayim la'Torah: Refer to 28:16:5:1. 1 The Torah therefore clarifies that the names of the twelve tribes must appear on the twelve stones (one tribe per stone), 2 rather than the Avos appearing on the first stone, and the tribes on the other eleven. 3
What does the Torah mean when it adds "Ish al Sh'mo Tih'yenah?
Seforno: Refer to 28:21:1:1. And it is forbidden to exchange either the stone or the Kavanah when engraving the names on them.
QUESTIONS ON RASHI
Rashi writes that they were in the order that they were born - Odem for Reuven
Mizrachi: Also Rashi means in the order of the Imahos (based on the order in which they first bore children) - Bnei Leah, Bnei Bilhah