Question:
Some things need to move with the times. One thing I find ridiculous is the two day festivals outside of Israel. Like we just had Shavuot, which the Torah says is celebrated for one day, but we celebrated it for two days. I know the reason. In times of old, each new month was announced when witnesses saw the new moon in Jerusalem. Outlying communities were never quite sure about the exact date, and so Diaspora Jews kept festivals for two days just in case. But today we do know the date, there is no confusion. So why still today do we keep two days outside of Israel for festivals that those in Israel celebrate for only one day?
Answer:
Just like every person has a body and a soul, so too every Jewish law has a body and a soul. The body is the apparent, obvious, surface-level explanation of the law. But the soul is its inner meaning, its spiritual significance, its deeper truth. And just as a person should not be judged merely on appearances, for beneath their façade they have much more to them than meets the eye, so too we should never rush to dismiss a Jewish law as irrelevant without investigating its inner meaning.
The technical reason for observing festivals for an extra day in the Diaspora is indeed due to confusion over the lunar calendar. Some months have 29 days, others have 30, and in times gone by this was determined by the rabbinical court in Jerusalem on a month by month basis. The announcement of a new month would not always reach far flung Jewish communities on time, and so, not knowing the correct date, they would keep two days for each festival, just to be on the safe side.
But this is only the body of the law, not the soul. The soul of the law is this. In the Land of Israel, the Holy Land, one day is enough to absorb the festival and its meaning. Outside of Israel, where the air is less receptive to holiness, we need two days to fully get it.
Each holy day in our calendar brings down a particular spiritual blessing. Pesach gives us an annual boost of freedom, Sukkos injects joy into our year, and Shavuos is when we receive Torah anew. In Israel, the connection is faster, and so the transmission of the festive energy is smooth and quick, done in a day. But in the Diaspora it takes longer. All divine blessings pass through the Holy Land first before they get to us, and so our connection is less direct and immediate. It takes time to absorb the holiness, and so we get two days. Any less would be too short to fully integrate the experience.
This reasoning is as relevant today as it ever was. The body is mortal, but the soul lives forever, and so even when the technical reasons for Jewish law seem outdated, their inner meaning, their soul, lives on.
~ Rabbi Aron Moss