The Mekhilta, the tannaitic midrash on Exodus dating to the 2nd century CE, zeroes in on a single phrase from the Passover laws to clarify exactly who was obligated to perform the blood ritual. The verse reads: "as a statute for you and for your sons" (Exodus 12:24). The question is sharp — why does the Torah specify "you and your sons" at all?
The answer hinges on an earlier verse. From the command in (Exodus 12:7), "And they shall take from the blood," the rabbis note that the language is broad enough to include everyone — men and women alike. Without further clarification, one might reasonably conclude that women were equally obligated to dip the hyssop and apply the blood to the doorposts.
The Mekhilta explains that the Torah therefore adds "as a statute for you and for your sons" as a deliberate limitation. The phrase "your sons" excludes women from the obligation of this particular ritual. The blood-touching of the doorposts was a commandment binding on men — fathers and sons — not on the entire household.
This kind of legal reasoning is characteristic of the Mekhilta's method throughout. The rabbis read every word as carrying independent force, and they use apparent redundancies to derive precise boundaries of obligation. What looks like a simple restatement turns out to be the Torah's mechanism for defining who stands under a commandment and who does not.