Friday is the traditionally accepted day of His crucifixion based on inclusive reckoning—considering any part of a day to be a whole day. Others calculate it as occurring on Thursday, allowing portions of three days and three full nights before His resurrection (Matthew 12:40). Some accept Jesus’ reference to Jonah’s three days in the belly of the whale as literally three solar days calculated sunrise to sunrise, favor Wednesday (Jonah 1:17; Matthew 12:40). A scholarly argument can be made for Wednesday, Thursday, or Friday.
Dating anything in the first century AD is extremely difficult, as several different calendars (lunar or solar) were in use. Additionally, even the chronology of the events in the last days of Jesus’ earthly life is significantly different in the synoptic gospels and John’s gospel. All four connect Jesus’ death with the Feast of Passover, but they do so in different ways and with differing emphases.
Confusion arises from the ambiguity of the phrase “day of preparation.” Was this day a preparation for the weekly Sabbath as in the synoptic gospels, or preparation for the Feast of Passover as recorded in John’s gospel?
Supporters of a Thursday 14 Nisan crucifixion reason this way: Jesus died and was buried before sunset on the day of preparation for the Passover feast. He was “three days and three nights” in the grave, considered by some to mean three nights (dusk to dawn) and three days (sunrise to dusk). His resurrection coincided with the Feast of First Fruits (Sunday 17 Nisan). The day prior to that was 16 Nisan, a regular Saturday Sabbath (Shabbat). The day before had to be Friday (15 Nisan), the date prescribed for Passover and first day of Unleavened Bread, which is always a feast day.
Friday 15 Nisan was Passover, a Holy Day (a Sabbath on whatever day of the week it occurs). That would make Thursday 14 Nisan a day of preparation for the Friday Sabbath and the day of His crucifixion.
The year of His crucifixion remains in question. No precise timeline of His final days can be constructed using the gospels. Little matter. The certainty of the events should be the focus, not the day or year.
If His crucifixion took place on Thursday, major events can be calculated as falling thus: Six days before the Passover (8 Nisan), Jesus rested in Bethany with Mary and Martha (John 12:1). Saturday (9 Nisan) was a Sabbath until sunset.
Jesus left Bethany after sunrise on Sunday (10 Nisan) and entered Jerusalem, allowing the crowd to acknowledge Him as king (John 12:13). If they crucified Him on Thursday 14 Nisan, the day of preparation for the annual Passover (15 Nisan a Friday), the sequence might have been as follows, based on my reading of the gospels:
Friday 8 Nisan