That was a one time commandment.
Here is a longer explanation to help you understand why.
Passover is every bit as important today as it was when it happened. It is not simply about the Jews being emancipated from physical slavery in Egypt. It is EQUALLY about their emancipation from a system of beliefs that enslaved their minds in superstition and obsessed with death. The rejection of the Egyptian obsessions of the worship of incarnate gods (pharaohs as deities) and reliance upon superstition and obsession with death and the afterlife to the detriment of THIS life ,emancipated the Jews as an eternal covenant nation people dedicated to worship of our incorporeal Creator who created all humans as equal in judgement and mercy.
Moses is the prophet who led Israel out of this spiritual servitude as well as helped to emancipate them from physical slavery. He isn't even mentioned in the seder ritual.
There were many miracles involved..and the reasons why it is important today can be understood by every Jew alive today
Look at the actual words that explain about Passover leading up to the Exodus from Egypt and you'll see how twisted much of the NON Jewish world has the story from the likes of the Cecil B DeMille version and from the replacement theologies that sprang up to negate Judaism : https://answersrip.com/question/index?qid=20130330235330AAtoS9R see my past answer and the reference to the book of Exodus
AFTER you’ve read that link you’ll see that God had Israel kill the representations of both the ram and sheep Egyptian deities represented by the cruel mangod Pharaohs in their presence and to dip hyssop, an herb used to purify the holy Egyptian temples and DIP it in the VERY LIFE ESSENCE (that’s what they believed blood to be) of their deity in their presence as an act of defiance and mark their doors with it in allegiance to the God of Israel who will demonstrate His power over their false gods. Then they were to roast and eat their false Egyptian god representation in the presence of the Egyptians without any recourse done to them, thus demonstrating the impotence of their man/god Pharaoh and their other false gods. In fact, they were “passed over” by the angel of death who instead punished the Egyptians for their idolatry and enslavement of mind and body. Pharoah had done this to God’s “first-born” ( You shall tell Pharaoh, 'Thus says the Lord, Israel is my son, my firstborn. Ex 4:22
12:12 I will pass through Egypt on that night, and I will kill every first-born in Egypt, man and beast. I will perform acts of judgment against all the gods of Egypt. I [alone] am God.
That is a very important passage there..NOTE..**God will enact judgment against the false gods..plural now..of Egypt. That was the purpose of the Passover sacrifice.**
12:13 The blood will be a sign for you on the houses where you are staying. I will see the blood and pass you by (pasach). There will not be any deadly plague among you when I strike Egypt.
12:27 You must answer, 'It is the Passover service to God. He passed over the houses of the Israelites in Egypt when He struck the Egyptians, sparing our homes.'
The people bent their heads and prostrated themselves.
The Passover sacrifice, be it a sheep or a goat, was NEVER a sin sacrifice. The sacrifice serves to demonstrate the people’s courage, as they take the Egyptians’ object of worship and slaughter and eat it in the service of the God of Israel!
Torah is clear that the sacrifice and eating of the lamb at Pesach was the killing and eating of the false god of Egypt to show allegiance to the real God. The continuation of the Paschal lamb sacrifice is an eternal remembrance of that deliverance from idolatry and slavery. This is why no uncircumcised male or Gentile could partake of the Paschal lamb. More than Israel has kept the Torah, the Torah has kept Israel..true in so many ways.
The reason that Passover has historically been the time of the worst persecutions of Jews throughout the spread of Christianity in Europe ( the blood libels and pogroms especially) is because of the extreme contradictions between the Torah's telling of the Passover and the purpose of the Paschal lamb, and the Christian redefinition of it being such a violation. Jews have historically been reluctant to point out that if they are being Biblical literalists with the book of Exodus and they call Jesus the Paschal lamb, it is THEY who label him a false god. That has incited murders of countless Jews over the centuries.
Don't take my word for this. Please. It is often a big shock when people read it in its own context, but shaking things up has a great deal to do with Passover....they abandoned a world-view imposed upon them for several generations by a powerful empire.
The lesson of the redemption of Israel from the immersion in a culture obsessed with death and the afterlife and belief in incarnate deities and who want to eliminate the path of Torah, is not so far from what Jews experience in the modern world .
The Paschal lamb was never a sin sacrifice and that’s very clear in the Torah and in Jewish history. No Paschal lamb was ever sacrificed to atone for sin.
There are many symbolic lessons in the story of the Exodus from Egypt and that the sages gave us in the creation of the seder to honor God’s commandments to memorialize the Passover.
Pharaoh was in a showdown with the God of Moses to see who was more powerful.
With every plague ..as God had told Moses he essentially set out to do:
God set out to show the Egyptians the truth..no man is a god or becomes one
Aspects of the story of the Passover also directly fit what could be described as a showdown between Pharaoh Ramses II as his own writings portray him; the mangod vs. God. Like the other Pharaohs before him, Ramses II believed himself to be a god, but he was one who styled himself as greater than all the others, and inscribed his name over that of other Pharaohs"
While the majority of Jews were already not living within walking distance of the Temple before it's destruction and not all Paschal lambs were sacrificed there, after the destruction of the Temple, the proper form of slaughter and sacrifice was deemed to be impossible for Jews by the first Rabbis. Some of this had to do with threat of persecution by the people they lived among for sacrificing animals considered sacred to them ( as had been the case IN Egypt, ironically..read the book of Exodus),They then developed a "seder" to honor the meanings of Torah and commandments for every generation to *remember* it, and greater importance over the fact that Israel had survived and still survives as a people dedicated to God alone..that death had PASSED OVER those who were dedicated to God..and for each generation, we remember this deliverance and the rededication to God that has enabled our existence to remain as an eternal covenant nation people.
After yet another attempt by a conquering people to destroy Israel/Jews and the nation people once again in exile, the early Rabbis restructuring of the seder helped focus on survival and the collective experience of Divine encounter and emancipation from idolatry and superstition around us as well as the continuing attempts to obliterate us. This is true for Jews today, look at France’s Jews , Jews fleeing a land that they had been living in for hundreds of years once again...