Or HaChaim on Exodus 28:2/אור החיים על שמות כ״ח:ב׳

1 ועשית בגדי קדש לאהרון…לכבוד ולתפארת, "And you shall make holy garments for your brother Aaron for splendour and beauty." These beautiful garments are an expression of joy, and will convince Aaron that Moses wanted him to appear robed in splendour. A person who only carries out a directive under duress does not go to the trouble of constructing such splendid garments for the person who replaces him in a role that had originally been slated for himself. Although the garments in question were a must for the person wearing them whenever he performed service in the Tabernacle, G'd followed the principle of allowing Moses to accumulate this merit for himself by allowing him to perform this commandment joyfully. In this instance, Moses' action represented a rapprochement between the souls of Moses and Aaron respectively. Perhaps G'd even meant that Moses should pay out of his own funds for these garments Aaron would wear during performing the functions of his new office. Although we have learned that as a rule the cost of the priestly garments was to be defrayed by the public purse (Yuma 3,7), the Talmud allowed for individuals to donate such garments and hand them over to the public. We need to explore the meaning of the word לכבוד, for honour, in this verse after G'd had already informed us of both the purpose and the nature of these garments. If all the Torah meant to tell us was that honour and glory would be conferred upon Aaron its wearer, what have we gained by this knowledge? Perhaps we can understand the meaning of this word by reference to Avodah Zarah 34. The Talmud quotes Rabbi Akiva as not having an answer concerning the question of what garments Moses wore (when he temporarily functioned as High Priest) during the seven days of the inaugural offerings of the priests. When he enquired in the academy they told him that Moses wore a white shirt while performing the service during those days. The fact that Moses wore only a white shirt during those days is clear evidence that the priestly garments themselves were not an essential part of the Temple-service except for Aaron and his sons. If any of the other priests performed the service without wearing their special garments the sacrifices offered by such priests would be acceptable to G'd. Accordingly, the word לכבוד means that these clothes are not for G'd's sake but for man's sake, merely for the sake of the image of the priest wearing them, especially when such a person was a priest on a permanent basis. Seeing Moses performed such service only on a temporary basis, he did not have to wear such garments.

2Alternatively, G'd wanted to give us a reason why the Torah commanded that the High Priest wear 8 garments, 4 made of white linen and four containing gold. The Torah says that the reason is לכבוד ולתפארת, for splendour and for beauty. We find the following comment in the introduction of Tikkuney Ha-Zohar. "The four white linen garments are an allusion to the four letters in the Ineffable Name, whereas the four golden garments are an allusion to the four letters in G'd's name א־ד־נ־י." We should remember that the Ineffable Name reflects G'd's attribute of תפארת, whereas G'd's name א־ד־נ־י reflects His attribute כבוד. According to this, the word לכבוד in our verse would refer to the golden garments, whereas the word לתפארת would refer to the white garments. The Torah listed varying degrees of holiness in ascending order, hence the attribute לכבוד precedes the attribute תפארת.

3G'd directed that eight garments were to be made for the High Priest in order for him to be able to obtain atonement for his people for the various imperfections that people are guilty of as a normal part of their lives. Aaron's wearing these garments would enable the Israelites concerned to achieve their proper place in the higher regions. Having said this, we need to understand why G'd was insistent that Aaron wear these garments whereas He did not provide similar garments for Moses to wear. The Talmud (Erchin 15) tells us that each of these eight garments conferred atonement for a specific type of sin. The reason that only Aaron and his sons were commanded to wear special garments was because such atonement could be obtained only by people who were intended to serve as priests all of their lives, something that did not apply in the case of Moses. Moses' function in temporarily serving as High Priest was only to obtain atonement for the sins of Aaron and his sons so that they could assume their office as priests. As a result, Moses wore only a white shirt when acting as priest.