The Mekhilta takes a phrase from the Passover laws — "it shall be to you for a keeping" (Exodus 12:6) — and asks what seems like a technical question with surprising depth. Does "keeping" mean you should keep the lamb until the fourteenth of Nissan and then slaughter it? Or does it mean you should keep it and slaughter it before the fourteenth?
The ambiguity is real. The Hebrew could be read either way. If "keeping" sets a deadline, then the lamb is selected early and slaughtered on the fourteenth. But if "keeping" describes an ongoing activity, the slaughter could happen anytime during the keeping period, meaning before the fourteenth.
The Mekhilta resolves this by pointing to a second verse. In the book of Numbers, when the Israelites observe the Passover in the wilderness, the Torah states explicitly: "And they offered the Pesach (Passover) in the first month, on the fourteenth day of the month" (Numbers 9:5). The fourteenth is the day of slaughter. The keeping period leads up to it but does not include it.
This kind of legal reasoning — using one verse to disambiguate another — is the backbone of rabbinic interpretation. What looks like a dry procedural question actually establishes a foundational principle of how God's commandments work. Every word in the Torah carries precise meaning. When a word seems redundant or ambiguous, it is an invitation to look deeper, to find the second verse that unlocks the first. The rabbis did not treat Scripture as approximate. They treated it as an interlocking system where every piece fits — if you know where to look.