Exodus 28:7

“It shall have the two shoulder pieces thereof, etc.] Which were two pieces that joined to the ephod, reaching from the arm holes to the shoulders both on the right and left, coming from before and behind; and meeting on the shoulders, were buttoned with two onyx stones, and covering the shoulders are called by this name: joined at the two edges thereof; the two edges of the ephod; not sewed thereunto with a needle, as Maimonides f815 and other Jewish writers think, but were woven along with it, and in the weaving was of the same with it: and so it shall be joined together; that is, the hinder and fore parts of the ephod in the shoulder pieces of it, shall be joined together by the two onyx…”

“(Compare Exodus 39:1-31.) Moses is now commanded to commit all that pertains to the offerings made to the Lord in the sanctuary to the exclusive charge of the members of a single family, who were to hold their office from generation to generation. In the patriarchal times, the external rites of worship had generally been conducted by the head of the tribe or family, in accordance with the principle involved in the dedication of the firstborn Exodus 13:2; Numbers 3:12-13. Moses, as the divinely-appointed and acknowledged leader of the nation, had, on a special occasion, appointed those who were to offer sacrifice, and had himself sprinkled the consecrating blood of the victims on the people…”

“Exo 39:4 Exodus 28:8”