1) Ch. 28, v. 1: "Nodov vaAvihu Elozor v'Isomor" Why are these names enumerated? We already know all of Aharon's sons by name.
2) Ch. 28, v. 9: "V'lokachto ES shtei avnei shoham" And you shall take two "shoham" stones The Ohr Hachaim Hakodosh asks why the word ES is used here. It seems that his question is based on the assumption that ES indicates either specific stones or stones that are already known by earlier reference. He answers that this refers to the "avnei shoham" mentioned in the beginning of parshas Trumoh 25:7. Although that verse mentions the need to bring numerous types of stones to fill the settings of the breast-plate, only "shoham" stones are mentioned by name. This is because of their unique function in the shoulder straps of the "eifode," besides being the second stone of the fourth row on the breast-plate, hence the word ES. This most puzzling. The word ES is used in so many other places and the Ohr Hachaim Hakodosh makes no issue of it. What is bothering him specifically here?
3) Ch. 28, v. 9: "Ufitachto a'leihem" And you shall etch out upon them In this verse and in verse 11, where we have the word "t'fatach," the verse expresses the etching procedure as a straightforward command, "you shall etch." However, by the etching of the names into the breastplate stones the Torah expresses it in a descriptive manner, "Pituchei chosom" (verse 21).
4) Ch. 28, v. 11: "Al shmos bnei Yisroel" ON the names of the bnei Yisroel Rashi is bothered with the word "al," as literally, it means UPON. How are the stones upon the names of the bnei Yisroel? He therefore explains that the intention of AL is WITH, You should etch the stones WITH the names. How can we explain the word AL in a literal manner?
5) Ch. 28, v. 35: "V'nishma kolo b'vo'o el hakodesh" And its sound will be heard when he enters the Sanctury The Rashbam writes that the sound emanates from the bells when he walks. This happens when the bells bang each other. Even though there are pomegranate shaped cloth balls between them, they still hit each other.
This is most puzzling. The gemara Z'vochim 88b clearly states that the bells were outer casings and an inner clapper, "zug v'inbal." The sound clearly comes from the inner clapper hitting the casing.
We have a similar difficulty with the words of the Lekach Tov. He writes that the sound emanates from the bells hitting the pomegranate shaped cloth balls. Although this should not produce a sound, miraculously, the cloth balls were hard and banged the bells so that they would ring. Again, this seems to run contrary to the words of the above-mentioned gemara.
The Rashbam goes on to say that the need for a sound system to accompany the Kohein Godol when he performed the service was to alert others in the Sanctuary to leave when he was doing the service, as per the verse in Vayikra 16:17, "V'chol odom lo yi'h'yeh b'ohel mo'eid b'vo'o l'cha'peir ad tzeiso." This is also most puzzling, as the verse is discussing the service of Yom Kippur. When the Kohein Godol enters to bring the bloods of the atonement ox and goat he does not wear the "m'il," which has the bells on its bottom, rather, only the four "white garments" of a regular Kohein.