The original Easter morning occurred on the first day of the Jews' week. (Matt 28:1, Mark 16:1-2, and John 20:1)
However, the first day of the Jews' week isn't the anchor for Jesus' resurrection. The real anchor is whatever night of the week that the paschal lamb is eaten, and the date for that night floats on the civil calendar, i.e. it isn't fixed like Christmas and birthdays.
The paschal dinner is always eaten at night; viz: after the sun goes down. For example: 2020's night for the dinner commenced at sundown the afternoon of Wednesday April 08, which means that Jesus would've died on the cross the afternoon of that same day because his death occurred during the afternoon of the day that the Jews were preparing for their paschal lamb dinner. (John 18:28, John 19:14)
The three nights that Jesus predicted in Matt 12:40 are counted by beginning with the night of the paschal dinner. Seeing as that night was scheduled to begin in 2020 with sundown the afternoon of Wednesday April 08, then Wednesday night would've been the first night; Thursday night the second night, and Friday night the third night.
The three days are counted by beginning with the sunrise that wraps Passover night, which in 2020 was Thursday April 09; so then that day would've been the first day, Friday the second day, and Saturday the third day, viz: Jesus' resurrection, had it taken place in 2020, would've commenced Saturday morning April 11.
I live in the metro area of Portland Oregon USA. The 2020 vernal equinox occurred at my location on March 19 @ 08:49 PM. Seeing as how that was before midnight, then in accordance with civil time, our first day of Spring that year was March 19.
However, according to Gen 1:4-5, Gen 1:14, Gen 1:16-18, and John 11:9-10; the hours of Day and Night are distinctly separate. So then, our actual our first day of Spring didn't begin till sunrise on March 20 while our first night of Spring began at 08:49 PM March 19.
Most everyone the world over knows that Easter commemorates Jesus Christ's resurrection; but the thing that needs to be told again and again is that without it, his crucifixion would've been futile.
● 1Cor 15:17 . . If Christ has not been raised, your faith is worthless; you are still in your sins.
Let me explain.
● Rom 4:25 . . He was delivered over to death for our sins and was raised to life for our justification.
The first half of that verse speaks of Isa 53:6
"We all, like sheep, have gone astray, each of us has turned to his own way; and The Lord has laid on him the iniquity of us all."
The second half of Rom 4:25 speaks of "justification" which is translated from the Greek word dikaiosis (dik-ah'-yo-sis) which means acquittal; defined as an adjudication of innocence.
In other words; it's by means of Christ's resurrection that people can get their records, spoken of in Rev 20:11-15, cleared so that on the books it's as though they've never been anything but 100% innocent.
Were I the Devil, the one component of Christianity that I would make my mission in life to invalidate is Christ's resurrection because it is by means of belief in his resurrection that hell-bound people have the opportunity to obtain an acquittal. Failure to believe it will result in losing their one God given chance to wipe the books; and thus they'll remain on a sure-fire path to the sum of all fears.
Q: How are sensible people supposed to believe in Christ's resurrection when Good Friday is so obviously a gross error?
A: It is impossible to produce three nights between Friday afternoon and Sunday morning. Even a little kid can see that. So what's the answer to this?
There are a number of feast days in the Old Testament that are just as much sabbaths as routine sabbaths. There's the first and last days of the feast Of Unleavened Bread, a.k.a. Passover (Lev 23:5-8), there's Yom Kippur (Lev 16:29-31), and there's the feast of Trumpets. (Lev 23:23-25)
It could be argued that whereas Yom Kippur and the Feast of Trumpets are specifically called sabbaths; the first day of the feast of Unleavened Bread isn't. It's set aside for an holy convocation. But routine sabbaths are called holy convocations too. (Lev 23:2-3). Anyway; John calls the first day of the feast of Unleavened Bread a sabbath (John 19:31) which pretty much settles it for me.
Passover sabbaths are interesting. Routine sabbaths always fall on the very same day of the week every time. But Passover sabbaths float; hence they can, and they do, occur on any given day of the civil calendar; sometimes even coincident with a routine sabbath; for example 2018 and 2019, and sometimes consecutive with a routine sabbath; for example 2008.
The Passover sabbath that occurred during the week that Jesus was crucified is a sneaky sabbath that easily escapes people's notice. By failing to reckon with it, they end up stuck with the Good Friday model; which of course is unworkable.
FAQ: If it's true there was a second sabbath in crucifixion week— one of the Passover sabbaths —then where would we place it in the chronology?
A: It began at sundown the afternoon of Christ's burial. (John 19:31)
FAQ: Where would we place the routine sabbath?
A: It followed on the heels of the Passover sabbath and is seen when the women went out to the cemetery. (Matt 28:1, Mark 16:1)
So the order of events is:
Sunday was resurrection day.
Saturday was a routine sabbath day.
Friday was a Passover sabbath day.
Thursday was crucifixion day.
FAQ: That's a total of four days. Isn't that one too many?
A: It's tempting to count the afternoon of Christ's burial as one of the days as per Matt 12:40 and John 2:19-22, but don't do it. Wait until the Jews' preparation for Passover comes to an end and they're ready to sit down and dine upon their lambs before starting to tally the days and nights or your chronology won't come out right. It's essential to leave crucifixion day set aside for the slaughtering of lambs; including the one on the cross.