Why Isn’t Resurrection Sunday, or Easter, on the Same Day Every Year? We know that Jesus died on the 14th day of the first month (Nisan, or Abib). “Your lamb shall be without blemish, a male of the first year; ye shall take it from the sheep, or from the goats. And ye shall keep it until the fourteenth day of the same month, and the whole assembly of the congregation of Israel shall kill it in the evening.” Exo 12:5, 6 He was resurrected “after three days” which would be either the 17th or 18th, depending on reckoning of the days. When we celebrate a birth date, for instance, April 5, it may be a Monday one year, Tuesday the next, on and on. The Passover date would do the same, but the year of the crucifixion, Jesus’ empty tomb was discovered on the “first day of the week.”
The early church fathers decided to keep the day of recognition of the resurrection of our Savior “on the first day of the week,” or Sunday. But why does it fluctuate by weeks from year to year? For instance, why not always the third Sunday of March, or April? The simple answer is that Resurrection Sunday was to be celebrated on the first Sunday immediately following the first full moon after the vernal equinox (first day of spring). This was true prior to 325 A.D. However, over the course of history beginning in 325 A.D. with the Council of Nicaea, the Western Church decided to establish a more standardized system for determining Easter based on astronomical charts.
In actuality, the date of the Paschal Full Moon is determined from historical tables when astronomers were able to calculate all full moons in future years, and now has no correspondence to lunar events. The Western Christian Church used these calculations to establish a table of Ecclesiastical Full Moon dates to determine the holy days on the Ecclesiastical calendar. Modified slightly in 1583 A.D., the Ecclesiastical tables have been used since. In Western Christianity, Easter is always celebrated on the Sunday immediately following the Paschal Full Moon.
The Paschal Full Moon can vary as much as two days from the actual full moon, with dates ranging from March 21 to April 18. As a result, Easter Sunday can range from March 22 through April 25. Confused? Try explaining that to friends!
For a similar reason, the actual Passover will fluctuate throughout the week, always being on the Jewish calendar date of 14 Nisan, while Good Friday is always the Friday immediately preceding Resurrection Sunday, or Easter. Only occasionally will Passover and Good Friday be the same day, happening last in 2015. In contrast, in 2016, Good Friday is on March 25th while the Jewish Passover isn’t until almost a month later, April 22.
The Passover is always to be remembered by the Jews but originally was not a “high day,” or holy day, but the day of preparation for the day that followed, the holy day being the first day of the Feast of Unleavened Bread (John 19:31), a seven day celebration. Eventually, Passover became included in the Feast of Unleavened Bread (John 22:1), now an eight day celebration. Incidentally, remember that these are holy days and not holidays!
Please feel free to add any additional commentary to this post; any additional information would be greatly appreciated.