The Torah uses the word "punished" in (Exodus 21:22) when describing the penalty for a man who injures a pregnant woman during a fight. "Then he shall be punished" — but punished how? The Mekhilta asks a direct question: does "punished" mean a monetary fine, or does it mean death?
The answer comes through a technique called gezerah shavah — a comparison of identical words used in different verses. The word "punish" appears here in Exodus, and it also appears in (Deuteronomy 22:19): "And they shall punish him a hundred shekels of silver." In that verse, the meaning is unambiguous. "Punish" means a monetary fine. Silver. Payment. Not execution.
Since the same word is used in both places, the Mekhilta concludes that "punished" in the Exodus verse also means monetary payment. Just as "punish" means money in Deuteronomy, so "punish" means money here. The man who caused the miscarriage pays a financial penalty to the woman's husband — he does not face the death penalty for this act.
This method of interpretation — linking verses through shared vocabulary — is one of the fundamental tools of rabbinic legal reasoning. A word does not change its meaning from one passage to another. If the Torah uses the same term in two different contexts, the clearer usage illuminates the ambiguous one.
The practical consequence is significant. By establishing that "punished" means monetary payment rather than death, the Mekhilta draws a clear line between causing a miscarriage through a fight — a serious offense requiring financial compensation — and intentional murder, which carries the death penalty. The Torah's legal system depends on these precise distinctions.