Parashas Chayei Sarah · Passuk 24:22
When the camels had finished drinking, the man took a gold nose-ring weighing a beka, and two gold bracelets for her arms, ten shekels in weight.
Rashi on Bereishis 24:22 (classical source on this passuk; not listed as a numbered Torah Temimah unit here).
Lemma / focus: בקע / שני צמידים.
English: Beka — an allusion to the shekels of Israel, a beka per head. And two bracelets — an allusion to the two Tablets joined together.
Derash on the verse (Rashi / midrashic symbolism) — not a formal named middah of the 13: the weights and the pair of bracelets are read as allusions to later Israelite institutions.
The nose-ring of a beka alludes to the half-shekel of the census; the two bracelets allude to the two Tablets; the gifts already signal the future of Israel.