John Calvin Commentary Exodus 39:1

"And of the blue, and purple, and scarlet, they made finely wrought garments, for ministering in the holy place, and made the holy garments for Aaron; as Jehovah commanded Moses." — Exodus 39:1 (ASV)

And of the blue, and purple, and scarlet. The description of the priestly garments, which is repeated in this chapter, is more accurate than it would have been if he had been speaking of some unimportant matter. And assuredly, since Christ was vividly represented in the person of the high priest, this was a most important part of the service of the Law.

We have elsewhere set forth how far it was from being an empty pomp, such as when papal sacrificers today, in order to acquire dignity, dazzle the eyes of the simple with the splendor of their vestments and their magnificent regalia. Rather, its purpose was to place before people's eyes all that faith ought to consider in Jesus Christ.

We have especially seen what great mysteries were contained in the miter, which was Holiness to the Lord, and in the ephod. In the ephod, the light of truth and integrity of life shone forth, and it contained the symbols of the ten tribes. Thus, the priest bore the people itself upon his shoulders and before his breast, so that in one person all might be presented intimately before God.

For this reason, he repeats seven times the clause, as the Lord commanded Moses; which certainly has the effect of awakening attention.