In my preparation for a message on Matthew 26:17-30, the text that includes the Lord’s Supper, I was reminded that there are those who would suggest that there is a discrepancy between John’s gospel and the synoptics—Matthew, Mark, and Luke—regarding exactly when Jesus ate the Last Supper and on what day Jesus died. The synoptics are clear that Jesus celebrated the Passover on Thursday and then died on Friday. John seems to indicate that the death of Jesus took place on the Passover, perhaps even at the very moment when the Passover lambs were being killed. And some would use this seeming discrepancy to suggest that the Bible contains an error, a contradiction. How, after all, could Jesus both eat the Passover meal one day and then die on the next day when the Passover lambs are being slaughtered?
All we need, however, to deal with this is a single, plausible, explanation for what we see in Matthew and John. I have read a few that would work. John tells us that the chief priests did not go into Pilate’s house because they wanted to be ceremonially clean so they could eat the Passover. Perhaps they were delayed in eating that meal on Thursday evening, but still planned to do so before sunset of Friday. Or, more likely in my opinion, they were not referencing the formal Passover meal only but the entirety of the sacred events of the combined Passover and Feast of Unleavened Bread. They wanted to be ceremonially clean for the week to follow with all its celebrations. Thus, when John calls the day of the crucifixion “the day of preparation of the Passover,” he could be telling us that, while Thursday evening was the Passover meal, Friday was the day of preparation for the special Sabbath observance that fell in the week that included Passover and the Feast of Unleavened Bread.
Another explanation is that there was a bit of variation in how different Jews understood their yearly calendar. We are aware that the sect at Qumran used a calendar that was a day off from that used by the priests. So, if Matthew and John were speaking from different calendars, there would be no discrepancy.
A third explanation comes not from the calendar but from the reckoning of when a day began and ended. John MacArthur explains it this way:
The answer lies in a difference among the Jews in the way they reckoned the beginning and ending of days. From Josephus, the Mishna, and other ancient Jewish sources we learn that the Jews in northern Palestine calculated days from sunrise to sunrise. That area included the region of Galilee, where Jesus and all the disciples except Judas had grown up. Apparently most, if not all, of the Pharisees used that system of reckoning. But Jews in the southern part, which centered in Jerusalem, calculated days from sunset to sunset. Because all the priests necessarily lived in or near Jerusalem, as did most of the Sadducees, those groups followed the southern scheme.
That variation doubtlessly caused confusion at times, but it also had some practical benefits. During Passover time, for instance, it allowed for the feast to be celebrated legitimately on two adjoining days, thereby permitting the Temple sacrifices to be made over a total period of four hours rather than two. That separation of days may also have had the effect of reducing both regional and religious clashes between the two groups.
On that basis the seeming contradictions in the gospel accounts are easily explained. Being Galileans, Jesus and the disciples considered Passover day to have started at sunrise on Thursday and to end at sunrise on Friday. The Jewish leaders who arrested and tried Jesus, being mostly priests and Sadducees, considered Passover day to begin at sunset on Thursday and end at sunset on Friday. By that variation, predetermined by God’s sovereign provision, Jesus could thereby legitimately celebrate the last Passover meal with His disciples and yet still be sacrificed on Passover day (MacArthur, Matthew 26:17-19).
There are, of course, other potential explanations out there for how Matthew and John could both be speaking the truth and not actually contradicting each other. And a thorough argument regarding those points is well beyond the purpose of this post. I simply want to make you aware that, if you hear someone suggest that this is a contradiction in the Bible, you know that people have done the work and the thinking to show us how it is not. And I would guess that the right answer is either the first or last ones mentioned above.