We observed the Passover Seder last evening as laid out in Exodus 12 on the evening of the 14th day of the 1st month of Nisan (Aviv). This is the time of the crucifixion of Yeshua (Jesus) as detailed in the synoptic gospels with some slightly confusing corroboration in the gospel of John which some interpret as being the day before. Jews continue to celebrate the Passover Seder on the 14th day as they determine it on their calendar and have done so continuously for thousands of years. It is followed by one week of the Feast of Unleavened Bread (Matzah) where no leaven is eaten and the home is kept completely free of it. We do our best to follow this practice as detailed in Exodus.
On the day after the Sabbath during Unleavened Bread, a ritual called the Waving of the Sheaf and/or Firstfruits celebrates the new barley crop and no new grain is eaten until this offering is made. This was the day Yeshua (Jesus) was resurrected and, in fact, 1 Corinthians 15 does identify him as the Firstfruits of the Resurrection.
Yeshua's early followers continued to celebrate Passover with their Jewish families and friends. Over time believers (later called Christians) for various reasons separated their observances from their Jewish peers. (This is a huge subject and too big to tackle here.) The emphasis shifted from the Passover Seder and Unleavened Bread to the crucifixion and resurrection of Yeshua.
At first these observances appear to have been held on the 14th of Nisan but because the resurrection occurred on Sunday a division grew within the Christian ranks over whether the resurrection should be celebrated on the 14th of Nisan or on the Sunday following. Those who held to the 14th of Nisan were called Quartodecimans. The martyr Polycarp held to the Quartodeciman position and claimed that the apostle John was the authority who passed this truth on to him. The group pushing for Sunday observance claimed that their apostolic justification came from Peter and Paul. Even while leaders of the factions could not settle their difference, they set an example by taking communion together publicly so that their congregations would not become enemies. (Polycarp and Anicetus did this in the late 2nd century.) The celebration of the resurrection in the church emphasized the communion, stations of the cross and both the crucifixion and the resurrection. The original dictates laid out in Exodus were forgotten.
Later after the emperor Constantine converted to Christianity he grew tired of all the bickering between the different bishops and he convened the Council of Nicea to try to bring some unity to the burgeoning faith. The doctrine of the Trinity began to take form and a new formula for dating the resurrection celebration was put forth. This change was not implemented until after Constantine died. The new dating involved the Spring equinox and did not depend upon the Biblical system of months. Growing anti-Semitism convinced the early Christians they did not want the dating of their most important day to depend upon Rabbinical councils and calendars.
I have given this long history with huge amounts of detail left out just to show how the Christian Church and Judaism diverged so greatly in their celebration. What didn't diverge is the terminology. In our Greek New Testament Passover is always referred to as "Pascha" a term of Aramaic derivation. To this day Pascha is the term that refers to the celebration of Yeshua's resurrection in Latin, Greek, Aramaic, Syriac, i.e. all the ancient Biblical languages. In the Catholic and Orthodox liturgies the term to describe this event is Pascha which is the Aramaic equivalent of Pesach in Hebrew referring to the sacrificial Lamb offered at Passover.
In English a new term shows up about 600 years after the Messiah, "Easter." This term of uncertain derivation, possibly from the Germanic goddess Eostre or possibly simply the direction East where the sun comes up, became the term to describe the resurrection in English, German and Dutch. The term has no relationship to any Middle Eastern Language and has no Semitic origin. It became so entrenched in English that the fast associated with Passover celebrated by English Jews in the 13th century was called "oesterfesten." When Tyndale did his landmark translation of the Bible into English he reserved the term Easter to describe the resurrection but refused to use that term to translate the Hebrew Pesach. So he invented the word "Passover" to be the English equivalent of Pesach. Contrary to the many "scholars" on FB, Easter is an older word than Passover and neither word has ever been used in the historic church. Neither of these terms is in the Hebrew Tanach or the Greek New Testament.
The objectionable things many find in Easter, bunnies, colored Easter egg hunts, etc. have nothing to do with the name and became a part of the celebration hundreds of years after the term became part of the English language.
All of this to say make sure you know what you are fighting and also make sure you have accurately defined the enemy. As so many trends currently seen in our society we have ended up becoming each other's enemies instead of opposing evil and those things actually destroying our society. This is just my plea--take the time to understand those who see things differently from you and actually find out what are the essential differences. And make sure that you fire your artillery at things you want destroyed.