John Calvin Commentary Exodus 28:9

"And thou shalt take two onyx stones, and grave on them the names of the children of Israel:" — Exodus 28:9 (ASV)

And you shall take two onyx-stones. That the connection between the priest and the people might be made clearer, God not only placed on his breast the memorials of the twelve tribes, but also engraved their names on his shoulders. Thus all cause for envy was removed, since the people would understand that this one man was not separated from the others for the sake of private advantage, but that in his one person they were all a kingdom of priests. Peter teaches that this was eventually fulfilled in Christ (1 Peter 2:5), just as Isaiah had foretold that priests of God and Levites would be brought from the Gentiles (Isaiah 66:21). John alludes to this in Revelation, where he says that we are all priests in Christ (Revelation 1:6).

But we must remember the reason why our High Priest is said to bear us on His shoulders. We not only crawl on earth, but we are plunged into the lowest depths of death. How then could we ascend to heaven, unless the Son of God raised us up with Him?

Since we have no ability in ourselves for eternal life, and all our powers of mind and body lie prostrate, we must be supported by His strength alone. Thus arises our confidence of ascending to heaven, because Christ raises us up with Him. As Paul says, we “sit together in heavenly places in Christ Jesus” (Ephesians 2:6). However weak we may be in ourselves, in this is all our strength: that we are His burden.

Therefore, this old type prefigured what Paul teaches: that the Church is “his body,” and “the fullness of him,” (Ephesians 1:22). It remains that each of us, aware of our own weakness, should rest on Christ. For when in foolish arrogance we exalt ourselves, we do not allow ourselves to be lifted up by Him, to be carried and sustained by His power. Let the proud then, by exalting themselves, fall to ruin, while Christ supports us on His shoulders.

These stones are called “stones of memorial” and, again, “for a memorial” to the children of Israel, as is also afterwards repeated of the twelve stones. Some interpret this to mean that “God may remember the children of Israel;” others, that “the priest himself may remember them;” still others, that “the children of Israel may remember that God is reconciled to them for the sake of the one Mediator.” But I simply interpret it that they were a monument of the mutual agreement between God and them, as if God would show by a visible sign that He embraced them and received them into His sanctuary whenever they were offered in this manner.