Why isn't the lamb blood on the lintel and the doorposts an eternal commandment?

Question

Exodus Chapter 12, Verses 21-24 read as follows (King James Translation)

21 Then Moses called for all the elders of Israel, and said unto them: ‘Draw out, and take you lambs according to your families, and kill the passover lamb.

22 And ye shall take a bunch of hyssop, and dip it in the blood that is in the basin, and strike the lintel and the two side-posts with the blood that is in the basin; and none of you shall go out of the door of his house until the morning.

23 For the LORD will pass through to smite the Egyptians; and when He seeth the blood upon the lintel, and on the two side-posts, the LORD will pass over the door, and will not suffer the destroyer to come in unto your houses to smite you.

24 And ye shall observe this thing for an ordinance to thee and to thy sons for ever.

Clarification: Exodus chapter 12. In traditional Judaism, this is not practiced in the Seder, nor was it practiced in the Second Temple period.

Answer 1

So the verses go like this:

21: Slaughter a lamb.

22: Put blood on the door and stay inside.

23: [Why?] The blood will prevent being smitten as God smites Egypt.

24: Do this in future generations too.

It seems pretty clear that 22 and 23 go together; the reason for putting blood on the door is because God's smiting Egypt. But God is only smiting Egypt this year, not future years. Ergo, 24 -- "do this in future generations" is referring back to 21. Yes, it needs a little bit of forward-scanning and back-scanning.

You were not the first to catch this! The classical commentary Ramban (Moses Nachmanides) says exactly this:

AND YE SHALL OBSERVE THIS THING. This refers to the Passover-offering itself, concerning which He had said above, and slaughter the Passover lamb, even though it is removed [by two verses from here]. It does not refer to the putting of the blood [upon the lintel and on the two side-posts, mentioned above] in the verse nearby, since only in the Passover of Egypt were they commanded to do so, [i.e., to put the blood upon the lintel, etc.], as it is said, For the Eternal will pass through to smite the Egyptians; and when He seeth the blood upon the lintel, etc. Similarly, the expression, and ye shall keep this service, means the offering of the Passover. A similar case [of a Scriptural expression that is connected with one that is far removed and not with the one nearby], is the verse, And also unto thy bondwoman thou shalt do likewise.

The Passover sacrifice is mentioned several other places in the Torah, and it's clear that the blood-and-door thing was only for in Egypt. (In fact, the Talmud tallies the ways that "Passover offering of Egypt" was the same, and different, compared to "the Passover offering of generations.")

So Year One Passover had blood on the door; as long as there was a Tabernacle or Temple (the next millennium or so, very roughly speaking), there was a Passover offering without the blood on the door. Today's Passover seder does not feature a Passover offering (in fact, we don't even eat any kind of dry-roasted meat, to avoid anyone even thinking that we're having a real sacrifice outside of Jerusalem) of any kind, and thus certainly doesn't have blood on the door.

As far as why no Passover offering is brought in Jerusalem today, that's a separate question. (There are a lot of technical obstacles from a strict Jewish-law perspective, and it's also not seen as politically feasible at the moment.)

The Talmud actually notes that when there was a Tabernacle or Temple, the blood (caught immediately from slaughter) was placed on the altar there, then the meat taken to a nearby home or inn for consumption. Thus the doorpost actually served as a decentralized altar of sorts in Egypt. After the Exodus, worship was more centralized. (So practically, by the time the slaughtered lamb made it to your house/hotel in Jerusalem, it wasn't dripping blood anymore.)

Answer 2

R Avraham ibn Ezra reads the verses precisely as you do but bows his head to rabbinic tradition.

Second Commentary Shemot 12:24

AND YE SHALL OBSERVE THIS THING. Many are of the opinion that the placing of the blood on the lintel and on the two side-posts is an obligation for all generations because 'this thing' is connected to the taking of the hyssop and dipping it into the lamb's blood. Furthermore, Scripture afterwards states: 'for that he passed over the houses of the children of Israel in Egypt' (v. 27).⁠ This interpretation would be correct from a logical point of view were it not for the true tradition which states otherwise.⁠ The correct interpretation is that 'this thing' refers to 'and kill the passover lamb'.⁠

Answer 3

Edit: Thanks to DoubleAA.

These questions can almost always be answered by looking at the context. In this case, the context is the next three verses:

“And it will be, when you come to the land that [The Name] will give to you, as that which was spoken;—and you shall observe this rite.

“And it will be, when your children say to you;—‘What is this rite to you?’

“And you shall say, ‘It is a Passover slaughtering to [The Name], who jumped over the houses of the Israelites in Egypt, during His smiting Egypt; and He saved our houses.’ And the People paid homage and bowed.”

Thus, the “eternal commandment” is defined by the following verses as the Pascal offering, a commandment which the Jews still have today, but cannot offer without the Temple.