Mark 14 tells of Jesus eating the Passover with his disciples. But after the Last Supper and when Jesus is captured, John 18:28 mentions the priests "themselves did not enter into the Praetorium so that they would not be defiled, but might eat the Passover". Does this mean there were two Passovers?
The Passover celebration in Jesus’ day was a complicated affair lasting a full 24 hour period. Remember, days on the Jewish calendar are counted from evening to evening. During the first evening, families celebrated the passover in their homes by consuming a lamb slain earlier that afternoon. As the law required, that sacrifice could not remain in the morning but had to be completely consumed over that evening.
The Passover meal was to be eaten on the first night of Passover in private homes by families. In Jesus’ day, the nation had adopted an additional ritual of a sacrificing a single lamb for the sake of the entire nation in the temple during the day of Passover following that first evening. In the week Jesus died, the Passover began on a Wednesday evening and concluded on a Thursday evening. So most Jews ate their meal Wednesday night according to Exodus and Deuteronomy, while the single, national sacrifice took place in the temple the following Thursday morning. That lamb became a meal for the priests and elders during that day prior to the end of Passover (and contrary to the Scripture).
So Israel celebrated one Passover celebration that stretched over a 24-hour period. Everyone ate one meal, with most eating it the night before as required by Scripture, but some religious leaders ate it on the following day following the national sacrificial lamb. This is why in John 18:28 the religious leaders were concerned about being defiled on the Thursday morning, because it would have disqualified them from participating in the national sacrifice and meal on that day.
In the gospels, we see Jesus following a similar pattern as the Lamb of God. He participated with His disciples in a Passover meal on the Wednesday night prior to His death (though there was no lamb present at His table because Jesus was the Lamb), and then the next morning Jesus hung on a cross as the Lamb of God for Israel and the world, even as the nation was sacrificing their national lamb at the temple.
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