Pentecost is the fiftieth day of Passover; however, if you check your calendar for this year, you will find that the Church is not celebrating Pentecost on the fiftieth day of the Jewish Passover, so what gives?
The confusion comes from the word ‘Easter.’ The holiday we call ‘Easter’ in English is called ‘Passover’ in other languages—and this is fitting, because Easter is the Christian Passover. Bearing this in mind, we find three methods of calculating Passover:
- The Jewish method, using the Jewish Calendar.
- In Scripture, the date of the Jewish Passover depends on the date of the spring harvest in Palestine. However, it became impossible to determine the date of Passover after the rebellion of Simon bar Kochba in AD 135, because the Romans banned all Jews from Jerusalem. (The ban lasted for centuries.) So the rabbis reformed the Jewish calendar at least twice, the first time was about AD 200. The current Jewish calendar was not in effect at the time of the Crucifixion.
- The Orthodox Christian method, using the Julian Calendar.
- Orthodox Christians calculate the date of Passover using a formula that was adopted at the First Ecumenical Council at Nicaea in AD 325. It was necessary to come up with a formula, because the changes in the Jewish calendar and the multiplicity of local calendars had caused rivalries and disputations about the proper date. The Nicene formula uses the Julian calendar as its base, since the Julian calendar was the civil calendar of the Roman Empire at the time. The Nicene formula compensates for the rabbinical calendar reforms and allows the celebration of the Resurrection on Sunday, as depicted in Scripture.
- The western Christian method, using the Gregorian Calendar.
- Western Christians use the Nicene formula to calculate Passover, which English-speaking Christians call ‘Easter,’ but base the calculation on the Gregorian Calendar. The Gregorian calendar is a reformed version of the Julian calendar that was promulgated by Pope Gregory in the 1580s. It corrected the inaccuracies in the Julian Calendar that allow Passover to wander into summer over time. The Gregorian Calendar has become our modern civil calendar.
Of the three methods, the western method seems to be the most accurate in reconstructing when Passover would fall if the first-century Jewish calendar were still in use. It compensates for the changes in the Jewish calendar and the inaccuracies in the Julian calendar.
Within each system, Pentecost is the fiftieth day of Passover. That is, the Jewish Pentecost is the fiftieth day of the Jewish Passover, the Orthodox Pentecost is the fiftieth day of the Orthodox Passover, the western Christian Pentecost is the fiftieth day of the western Christian Passover, which we confusingly call ‘Easter’ in English.
You can read more information about the calendars.
I say ‘of’ Passover and not ‘after’ Passover because the counting begins with one rather than zero. That is, if you are counting off the squares on the calendar, and you start by calling Passover (or Easter) as ‘one,’ when you say ‘fifty,’ your finger will be on Pentecost.