Komentarz do Wyjścia 35:27

והנשאם הביאו AND THE PRINCES BROUGHT [ONYX STONES] R. Nathan asked, “What reason had the princes to give their contributions at the dedication of the altar (Numbers 7:12ff.) first of all the people, whereas at the work of the Tabernacle they were not the first, but the last to contribute?” But — replied he — the princes spoke thus: “Let the community in general contribute all they with to give and what will then be lacking we shall supply” But when the community gave everything needed in its entirety — as it is said, (Exodus 36:7) “For the stuff they had was enough [for all the work to make it, and some was left]” — the princes asked, “What can we now do?” therefore הביאו את אבני השהם וגו׳ THEY BROUGHT THE ONYX STONES etc. That is why they were the first to contribute at the consecration of the altar. Because, however, they were dilatory at the beginning, a letter is missing here from their title (thus intimating that something, viz., zeal was lacking in them): for it is written והנשאם instead of והנשיאים (Numbers Rabbah 12:16).

והנשיאים הביאו את אבני השהם, and the princes brought the onyx stones, etc. The reason that these precious stones are listed only after such relatively inexpensive contributions as the spun goats' hair by the women is, that the princes tarried and were the last ones to make their contributions.

והנשיאים הביאו את אבני השוהם, these were the gemstones on which the names of the tribes were inscribed.