The Torah describes a young woman sold into servitude by her father and establishes the conditions under which she goes free. Rabbi Eliezer interprets the verse "Then she shall go out free" (Exodus 21:11) as referring to a specific biological milestone: she becomes a bogereth, a fully mature woman. At that point, her servitude ends automatically.
The next phrase — "without money" — seems redundant. If she goes out free, obviously no payment is involved. But Rabbi Eliezer reads "without money" as code for something else entirely: the appearance of signs of puberty. The Hebrew phrase hints at physical development that marks the transition from girlhood to early adulthood.
This creates two distinct stages of release. The first is puberty, when initial physical signs appear. The second is full maturity — the bogereth stage — when development is complete. Each stage has legal consequences for the terms of servitude.
The Mekhilta then addresses what happens in the absence of these physical signs. If the years of service expire before the biological milestones arrive, the woman's release is calculated financially. The value of the years she has already served is deducted from the value of the years remaining in her term, and the balance determines the terms of her departure.
The teaching reveals how rabbinic law used biological reality as a check on legal contracts. A father's right to sell his daughter into service was not unlimited. Her own body set boundaries that no agreement could override. Physical maturity functioned as an automatic release mechanism, ensuring that the law recognized her emerging autonomy regardless of whatever financial arrangements had been made on her behalf.