Tafsiran Keluaran 28:38: Rashi, Chizkuni, Or HaChaim & Rashbam

ונשא אהרן AND AARON SHALL BEAR [THE INIQUITY OF THE HOLY THINGS] — The word נשא is an expression of forgiveness, but nevertheless it does not move from (lose) its ordinary meaning of “bearing”: Aaron bears the load of iniquity so that it follows that the iniquity is lifted off the holy things.

והיה על מצחו תמיד, “it shall always be on his forehead.” Whenever he wears the mitre (turban) on his head he must also wear the crown of holiness, i.e. the Tzitz headband. It had the tetragram engraved on the golden band.

לרצון להם לפני ה׳. "that they may be accepted on their behalf by G'd with goodwill." We need to understand why the two words "Holy unto G'd" possessed the ability to attract G'd's goodwill. Perhaps the word "Holy" referred to the people of Israel. We find Israel described as "Holy" by Jeremiah (Jeremiah 2,3). The word "unto G'd" are meant to convey that the Jewish people as a whole are devoted and dedicated to G'd. This fact (and not merely the words on the ציץ) ensure G'd's goodwill towards the people. This is the mystical dimension of the words אני לדודי ודודי לי, in Song of Songs 6,3. Solomon means that "if I am devoted to G'd, as a result G'd i.e. דודי, will turn His benevolent attention towards me."

את עון הקדשים [HE SHALL BEAR] THE INIQUITY OF THE HOLY THINGS — atoning for the blood and fat of sacrifices which had been offered when they were unclean, as we have learned (Pesachim 17b; Yoma 7a): What iniquity is it that it (the Plate) bears (atones for)? If you say that it is the iniquity caused by פגול — but it is already said in reference to this, (Leviticus 19:7) “it cannot be atoned for”! If you say it is the iniquity caused by נותר — but it is said in reference to this, (Leviticus 7:18) “It shall not under any circumstances be accounted [unto him] as a sacrifice”! Nor can one say that it (the Plate) atoned for the iniquity of the priest who offered a sacrifice when he was unclean because it is stated here, “[shall bear] the iniquity of the holy things” and it does not state “the iniquity of those who offer the sacrifices” — thus it (the Plate) atones only in so far as to make the sacrifice a fitting one if there had been anything irregular about it.

והיה על מצחו תמיד — It is not possible to say that this means that it should be on his forehead continually because, as a matter of fact, it was on it only at the time of the sacrificial service. But the word תמיד is to be connected with the words that follow: “continually to make atonement for them”, even if it be not then upon his forehead, i. e. when the High Priest was not officiating, and therefore was not wearing the Plate, at that time when the unclean animal was being sacrificed by an ordinary priest. But according to the opinion (if we adopt the opinion) of him (Rabbi Judah) who says that only whilst it was on his forehead did it atone and effect pardon, and that if it was not on his forehead it did not effect pardon, the following inference must be derived from the phrase על מצחו תמיד: it informs us that he must constantly touch it whilst it is on his forehead, so that he should not divert his attention from it (Yoma 7b).