The Torah uses an unusual doubled phrase when describing how the Passover lamb must not be prepared: "vashel mevushal" — literally something like "cooked, cooked" or "boiled, boiled" (Exodus 12:9). The Mekhilta asks what this redundancy accomplishes, and the answer reveals the precision of biblical legislation.
The doubled expression creates a double prohibition. It makes a person liable both for eating the Pesach (Passover) raw and for eating it cooked in liquid. The lamb must be roasted over fire — nothing else. But what about over-roasting? If someone burns the lamb on the fire until it is charred beyond recognition, are they also in violation?
The Mekhilta considers this possibility and rejects it. The Torah says, "but roasted in fire." Roasting in fire, even excessive roasting, still falls within the commanded method of preparation. The prohibition targets deviation from fire — either by not cooking at all (raw) or by using a different medium (boiling, stewing, braising). Over-roasting is still roasting. Under-cooking is not.
The legal reasoning is tight as a drum. "How, then, is vashel mevushal to be understood? As making him liable for what is raw and what is cooked." Two words, two violations. The doubling is not poetic emphasis — it is legislative expansion. Each iteration of the word adds a category of forbidden preparation. This is how the rabbis understood divine language: God does not repeat Himself for rhetorical effect. Every repetition in the Torah creates a new legal reality.