Charles Ellicott Commentary Exodus 31:10

"and the finely wrought garments, and the holy garments for Aaron the priest, and the garments of his sons, to minister in the priest`s office," — Exodus 31:10 (ASV)

The cloths of service. — Modern critics generally suppose the state robes of the high priest to be meant (Keil, Knobel, De Wette, Kalisch, Cook); but the Rabbinical interpreters understand the cloths in which the ark and other vessels of the sanctuary were wrapped when the camp was moved from place to place . These, like the cloths spoken of here (Exodus 39:1), were to be of blue, and purple, and scarlet; and it would be natural to distinguish them from the “holy garments,” as is done both here and also in Exodus 35:19, Exodus 39:1, and Exodus 39:41.

They had, however, not been previously mentioned in the directions. Perhaps the true explanation is that under the words “cloths of service” (bigdey sĕrâd, or bigdeh hassĕrâd) are included both the garments of Aaron and also those of his sons, the two later clauses of the verse being exegetical of the first clause. In that case, we should translate: The robes of service, both the holy garments for Aaron the priest, and also the garments of his sons. Exodus 39:41 is decidedly favorable to this interpretation.