Day of Preparation

The "day of preparation" is neither a holiday nor a holy day. There is nothing official about it. Perhaps the biggest cause of confusion is that the translators chose to capitalize it, making it seem like a proper noun.

For the weekly sabbath, and those high holidays that are treated as sabbaths (High Sabbaths - Wikipedia), people must do extra work preparing for the next day when they won't be cooking meals etc. (just as the Israelites in the desert gathered double manna the day before each sabbath). This is why the day before each sabbath, whether weekly or annual high day, is referred to as a day of preparation.

Consider 2023:

On Wednesday April 24, during the daytime people prepare food etc. for the annual Passover high holiday and rid their homes of all traces of yeast in preparation for the Days of Unleavened Bread. (In ancient times, at around 3 pm, the Passover lambs were slaughtered.) In the Hebrew calendar, this is Nisan 14.

At sunset, the high holiday begins, and the Passover seder is eaten.

That night, and Thursday daytime are a high holiday, treated as a sabbath, with no work.

Friday daytime is another day of preparation, albeit a much lesser one, this time for the weekly sabbath, which begins at sunset.

The weekly sabbath ends when the sun sets on Saturday.

On Sunday (the first day of the week immediately after the first weekly sabbath during the Days of Unleavened Bread), priests make a wavesheaf offering. Starting from that Sunday, 7 weeks are counted until Sunday, 50 days later (Pentecost).

The same thing happened nearly 2000 years ago, in AD 31:

Tuesday evening, Jesus eats his "Last Supper", which is not the Passover seder, with his disciples.

Wednesday, the 14th of Nisan (25th of April), is the day of preparation for the high holiday ("Therefore, because it was the Preparation Day, that the bodies should not remain on the cross on the Sabbath (for that Sabbath was a high day), the Jews asked Pilate that their legs might be broken, and that they might be taken away." — John 19:31). Jesus is tortured and executed, dying at about 3 pm, and hurriedly buried before sunset (about 6 pm) when the annual sabbath begins.

That evening the already prepared Passover seder is eaten. (A partial lunar eclipse, which can cause the moon to appear red, occurred on Wednesday 25 April in the year 31.) Everyone then rests during the high holy day until sunset on Thursday.

Friday is a normal Friday, the first chance the women have to buy spices ("And when the sabbath was past, [the women] had bought sweet spices, that they might come and anoint him." — Mark 16:1). They prepare the spices during the day on that Friday. They then rest when the weekly sabbath begins at sunset. ("[the women] returned and prepared spices and fragrant oils. And they rested on the Sabbath according to the commandment." — Luke 23:56). Notice that there are two distinct sabbaths, the high sabbath before Friday, and the weekly sabbath after.

Just before sunset on Saturday, when the sabbath ends, exactly three days and three nights after his burial, Jesus is resurrected ("For as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth." — Matthew 12:40).

Very early Sunday morning, long before sunrise, the women bring the spices to the tomb and find it empty ("Now on the first day of the week Mary Magdalene went to the tomb early, while it was still dark, and saw that the stone had been taken away from the tomb." — John 20:1). Matthew 28:1 refers to that Sunday morning as "In the end of the sabbath …". Some versions of the Bible translate that as "After the sabbaths" (e.g. LITV, CLNT, YLT, Fenton), the plural confirming that there was more than one sabbath. Later that day, the resurrected Jesus becomes God's firstfruit, as had been symbolized by the wavesheaf offering.

Referring to Joel 2:31, Acts 2:20 says "The sun shall be turned into darkness, and the moon into blood, before that great and notable day of the Lord come". Apocrypha also refer to a blood-moon on the night of the crucifixion.

On Wednesday 25 April in the year 31, a partial lunar eclipse occurred, causing the moon to appear red.

31 is the only year within a decade in which Passover began on a Wednesday.

Biblical Herumenatics