The Torah describes the blood ritual of the first Passover in Egypt: the Israelites were to apply the blood of the Paschal lamb to the lintel and the two doorposts of their homes. But a subtle question arises from the verse's phrasing — does the order in which you apply the blood matter?
The verse says "you shall touch the lintel and the two doorposts," placing the lintel first. One might conclude from this sequence that the lintel must be marked before the doorposts. If someone applied blood to a doorpost before touching the lintel, perhaps the entire ritual would be invalid. The order stated in the verse would become a binding legal requirement.
The Mekhilta rejects this reading by pointing to a second verse. (Exodus 12:7) states, "And he shall place it on the two doorposts and on the lintel" — reversing the order entirely, putting the doorposts first and the lintel second.
Two verses, two different sequences. If the Torah meant to prescribe a fixed order, it would not contradict itself. The fact that one verse puts the lintel first and another puts the doorposts first proves that no specific order is required. "In either case he has fulfilled his obligation."
The ruling illustrates a core principle of rabbinic interpretation: when two verses present the same action in different sequences, the Torah is signaling that the sequence is not legally binding. The act matters. The order does not. What God required that night in Egypt was blood on the door — not a particular choreography of application.