Gerah

The gerah is the smallest weight-unit named in the UPDV. It surfaces only as the fixed fraction inside the sanctuary-shekel definition: twenty gerahs make one shekel, and that ratio is the unit's whole canonical use.

Twenty Gerahs to the Shekel

The half-shekel atonement-tax in Exodus introduces the ratio in passing, embedded in the parenthesis that defines the standard: "This they will give, everyone who passes over to those who are numbered, half a shekel after the shekel of the sanctuary (the shekel is twenty gerahs); half a shekel for an offering to Yahweh" (Ex 30:13). The same parenthesis closes the vow-redemption legislation in Leviticus: "And all your estimations will be according to the shekel of the sanctuary: twenty gerahs will be the shekel" (Le 27:25). In the Numbers redemption-payment for the surplus firstborn over the Levites, the formula is repeated in the same form: "you will take five shekels apiece by the poll; after the shekel of the sanctuary you will take them (the shekel is twenty gerahs)" (Nu 3:47). And the firstborn-of-man redemption in the priestly portion-laws gives the identical parenthesis: "you will redeem, according to your estimation, for the silver of five shekels, after the shekel of the sanctuary (the same is twenty gerahs)" (Nu 18:16).

Ezekiel's Restored Standard

Ezekiel, prescribing the weights of the restored community, repeats the ratio and then anchors a higher unit on it: "And the shekel will be twenty gerahs; twenty shekels, five and twenty shekels, fifteen shekels, will be your⁺ maneh" (Eze 45:12). The gerah is here, as in the Pentateuchal half-shekel and redemption legislation, the small fixed twentieth that makes the sanctuary-shekel a stable measure.