"Money shall he restore to its owner" — when someone's animal falls into another person's uncovered pit and dies, the pit-digger must pay compensation. The Torah specifies "money." But the Mekhilta asks: can the pit-digger pay with a beast instead of cash?

The answer comes through a gezeirah shavah — a verbal analogy. The phrase "and the carcass shall belong to him" appears both in this passage and in (Exodus 21:36), which deals with an ox that gores another ox. In that second passage, the Torah says: "Then shall he pay an ox for an ox, and the carcass shall belong to him." There, the payment is explicitly made with a beast — an ox for an ox.

Since both passages use the same phrase — "and the carcass shall belong to him" — the Mekhilta transfers the payment methods between them. Just as the ox-for-ox case allows payment with a beast, the pit case also allows payment with a beast. And just as the pit case specifies money, the ox-for-ox case also allows payment with money.

The gezeirah shavah works in both directions, creating flexibility in both passages. The pit-digger can pay with money or a beast. The ox owner can also pay with money or a beast. Neither passage alone permits both options, but the verbal link between them creates a reciprocal expansion. Each passage grants the other an additional mode of payment that it did not originally specify.