Does the jewish Passover and Christian Pesaha fall on the same date every year?

The two days will always happen at least around the same time. Jewish Passover (Pesah in Hebrew) and Easter can happen on the same day, but strangely enough, under the current rules used for the Jewish calendar, the Gregorian calendar, and the calculation of the date for Easter, the Jewish Passover and Holy Thursday (or Maundy Thursday, Pesaha in Syriac) can actually never occur on the same day. The reason for this was so strange and obscure that I actually had to do some research as to why.

In the Church, Easter is what we call a “moveable feast,” which means simply that the date of the feast can move around. This is in contrast to “fixed feasts,” which happen on set days (e.g. Christmas is always December 25th). There is a very particular method for calculating the date of Easter, which is done according to a combination of the lunar cycle and the regular calendar: Easter occurs on the first Sunday after the first full moon after the spring equinox (March 21st). That means that the earliest possible date of Easter in any year is March 22nd, and the latest possible date is April 25th. This way of determining the date for Easter was set by the Church in 325 AD at the Council of Nicaea. Before then, the Church borrowed the Jewish calendar to calculate the date for Easter.

Here’s where things start to get confusing. The reason that the Church switched away from using the Jewish calendar is because of how tricky it was to accurately determine when Easter would be. That’s because the Jewish calendar, unlike our current calendar (the Gregorian calendar), is a lunar calendar, in which months are determined by the cycles of the moon. The regular lunar cycle is 29-30 days, which is roughly the length of a calendar month… roughly. Since there are still 12 months in the year, this means that the Jewish calendar would end up with a shortage of days compared to the earth’s solar cycle (354 days in the Jewish calendar vs 365 in the regular solar cycle). A few thousand years ago, rabbis decided to try and correct this by periodically adding an extra month–a kind of 13th “leap month.” Unfortunately, this wasn’t always reliable either, so this was standardized even further so that the leap month gets added 7 times every 19 years of the Jewish calendar (“19 years” because that’s the length of the Metonic cycle, which is how long it takes for the lunar cycle to start and end on the same days again).

Confusing enough? The early Church apparently thought so too. The Church decided it was in everyone’s best interest to reduce these complications and set an easier formula for determining the day for Easter, like mentioned above. But if that wasn’t complicated enough, there’s still some very strange things that happen because of these calendar differences. Because of the Jewish calendar’s leap month, there are 3 times every 19 years where the Jewish Passover happens a month later than Easter. And even stranger… and this actually brings us back to the original question… Jewish Passover can’t ever land on Holy Thursday (Maundy Thursday). Even though Holy Thursday is the actual scriptural night of the Pesah (Passover), rules were added later to the Jewish calendar which made it so that the year can’t begin on certain days of the week. It turns out that if Passover started on Thursday evening, then it would make Judaism’s two high holy days, Rosh Hashanah and Yom Kippur, land on Sunday, which isn’t allowed because the Jewish Sabbath day (Saturday) would require people to rest, preventing people from preparing for the feasts.

All these calculations make it surprisingly difficult to accurately pinpoint the original day when Jesus celebrated the Last Supper with the Apostles. However, considering the fact that both Passover and Easter have been moveable feasts since the beginning, we can be at peace that we are being faithful to the command of Christ on whichever day we happen to celebrate the Paschal Triduum!