Figuring out when Jesus ate the Last Supper with his disciples and which day he died on the cross is not easy. Why? First of all, Jews started new days each evening! Our days (in the Gregorian calendar) begin and end in the middle of the night and consider daylight the middle of the day. Jewish days began at dusk with the first half of a day being the dark night and the second half of the day being the daylight. That's why Genesis 1 says, "there was evening and morning on day one." That's also why we get confused about the timeline of Jesus' death and resurrection in the Gospels.
If Jesus actually died on Friday afternoon when we celebrate 'Good Friday,' then he would have only been in the grave for 2 nights. But Jesus said he would be in the grave for 3 nights. So either Jesus is wrong (see matthew 12:40), or our holiday is wrong. It's worth investigating.
- Preparing for the Passover. When did Jesus eat the 'Last Supper' with his disciples? Mark 14:12–16; Matt 26:17–19; Luke 22:7–13 put it on the evening after "the First Day of Unleavened Bread" before Passover. That does not refer to the first day of the 7-day Feast of Unleavened Bread on Nisan 15-21 in the Jewish calendar or to Passover on Nisan 14. Rather the "First Day" was the day before the 8 days of celebration (before Passover & the 7-day Feast) when Jews removed all unleavened bread. It would be Nisan 13 in the Jewish calendar before the day of Passover on Nisan 14.
- Passover in Jewish Homes. Philo of Alexandria in De Vita Mosis and Josephus in the Jewish Wars tell us that Jews had two different ways they observed the Passover in Jesus' time. Most people observed Passover in their homes on Wednesday evening as Nisan 14 began. But Priests celebrated Passover by sacrificing the Korban Pesach in the Temple on Thursday afternoon as Nisan 14 ended with the close of daylight. Josephus estimates that 250,000 lambs were slaughtered in the city of Jerusalem with only a few thousand sacrificed in the Temple.
- Jesus Ate And Died on Passover. Jesus ate the Passover meal along with most people in Jerusalem on Wednesday night (modern calendar) or the beginning of Nisan 14 (remember Jewish calendar days start at sunset!) before the 7-day Feast of Unleavened Bread on Nisan 15-21, also called Passover Week at the time. That is how Jesus both ate the Passover with his disciples one evening and was also killed the next afternoon when the main Passover lamb ('Korban Pesach') was slaughtered in the Temple.
- Jesus Died on Thursday. Jesus was killed on Thursday afternoon (modern time) when priests slaughtered the main Passover Lamb in the Temple on Nisan 14 before the 7-day Feast of Unleavened Bread began with a special Sabbath (Leviticus 23:6-7) on Nisan 15 (Thursday evening on our modern calendars).
- Gospels Use Different Clocks. Synoptic Gospels put Jesus' crucifixion 'at the sixth hour' (Matt 27:45; Mark 15:33; Luke 23:34) but John puts Jesus before Pilate 'at the sixth hour' (John 19:14). There is no contradiction because John used Roman time for his audience in Roman Asia Minor (thereby meaning 6am for the trial--the 6th hour after midnight) while the Synoptic Gospels all used Jewish time (thereby meaning Jesus was crucified at noon--the 6th hour after sunrise). Remember the Gospels adapted details of each story for different audiences.
- Special Sabbaths. The week Jesus died had 2 Sabbaths including a special 'high sabbath' on Friday. Leviticus 23 says the first day of the Feast of Unleavened Bread was a special high Sabbath on Nisan 15 regardless of the day of the week it fell on. So both Friday (Nisan 15) and Saturday (Nisan 16) were Sabbaths the week Jesus was crucified. The first special Sabbath on the week Jesus died started the evening right after Jesus was hastily buried in the garden tomb of Joseph of Arimethea (Thursday evening in modern calendars, or the beginning of Nisan 15 in Jewish calendars which would be a Jewish Friday). John 19:31 describes the "special Sabbath" that took place on Friday after Jesus was buried.
- Burial Before the Special Sabbath. Jewish authorities wanted Jesus tried, killed and buried before this special high Sabbath mentioned in John 19:14,31,42 (see also Matthew 26:62). Luke 23:54 and Mark 15:42 put Jesus' burial on the 'Day of Preparation,' or better translated 'Sabbath Eve'--which would be Thursday afternoon in our calendars before the special Friday Sabbath that began at dusk on Thursday evening (in our Gregorian calendars).
- Resurrection After Both Sabbaths. Women discovered the empty tomb on Sunday around dawn after the 2nd Sabbath ended. The Sabbath was Saturday night and day, which equated to Nisan 16 in the Jewish calendar. Matthew 28:1 uses plural "Sabbaths" to make it clear that the special Friday Sabbath and normal Saturday Sabbath had transpired during 3 nights between Jesus' death on Thursday afternoon and resurrection on Sunday morning.
- 3 Nights in the Grave. Death on Thursday afternoon (modern time) or end of Nisan 14 (on the Jewish calendar) and resurrection on Sunday morning matches Jesus' prediction: “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,” said Jesus (Matthew 12:40).
- Resurrection on the Day of Firstfruits. The Sadducees who controlled the Temple in Jesus' day celebrated the Festival of the Firstfruits on Sunday after the normal weekly Saturday Sabbath during the Feast of Unleavened Bread. So Jesus rose on the day of the Firstfruits, and Paul explains the theological significance in 1 Corinthians 15. Jesus was the first of many more resurrections to come.
Those 10 facts will hopefully give you an easier way to understand the events of holy week. It is hard navigating ancient texts when we don't know that folks celebrated the same holy day at different times or how the same words could refer to different things--like the word Sabbath!
I believe the greatest confusion in the timeline has stemmed from 3 factors: (1) Jewish People observed Passover in their homes on Wednesday evening (according to our Gregorian calendar) or as Nisan 14 began (in the Jewish calendar) whereas Priests celebrated Passover by sacrificing the Korban Pesach in the Temple on Thursday afternoon as as the Jewish day of Nisan 14 ended with the close of daylight on Thursday, (2) the reference to 'the First Day of Unleavened Bread' in Mark 14:12–16; Matt 26:17–19; and Luke 22:7–13 actually describes how people prepared for the 8-day celebration on Wednesday Nisan 13 before Passover on Nisan 14 and the 7-day Feast of Unleavened Bread on Nisan 15-21, and (3) reference to multiple Sabbaths with the first one on Nisan 15 being a "high Sabbath" on Friday (John 19:31) beginning the Feast of Unleavened Bread and the second Sabbath being a normal Saturday Sabbath on Nisan 16. Understanding these phrases and facts should give you a clearer understanding of how Jesus ate Passover on Wednesday evening, died Thursday afternoon, and was in the grave Thursday, Friday, and Saturday nights before his resurrection on Sunday.
Although the facts point to a death on Thursday afternoon, don't let it detract from your Good Friday services. We have no idea when Jesus' birthday really was, but you can still experience the heart of Christmas on an arbitrary day in December. So being one day off on when Jesus died shouldn't be a big deal.
But make sure you dig into the significance of Passover and Firstfruits each year to uncover the full theological significance of Jesus' death and resurrection. Getting the timeline right is only valuable when you see what it reveals about the significance of Jesus' final days. He was the final Passover lamb--crucified at the same time as the main lamb was slaughtered on the Temple altar. And he is the first of many resurrections to come. He was the one his people had been waiting for.
If you want to read how Jesus' last supper was a 'covenant meal' that makes the meaning of communion more than just saying 'thanks' for forgiving our sins, read chapter 8 "The Lost Meaning of the Last Supper" in my book Reenacting the Way (of Jesus).