The original Passover instructions clearly stipulate that Passover is a single day—Abib 14—followed by the seven-day Feast of Unleavened Bread, beginning on Abib 15 (Exodus 12:6-20; Leviticus 23:5-8; Numbers 9:2-5). These original instructions also direct the Israelites to keep the Passover in individual homes rather than at the Tabernacle or Temple—to catch the blood of the lamb in a basin and smear it on the doorposts and lintel of the house (Exodus 12:22).
Over time, though, the children of Israel moved farther from God and His instructions. During the reigns of the kings, Israel and Judah, now separate nations, adopted many practices from the pagan cultures surrounding them, with the kings often leading the way. However, a few kings of Judah, such as Hezekiah and Josiah, stand out for their dedication to God. Under these zealous monarchs, various religious reforms were instituted to try to bring Judah back to God's way. Among other reforms, they reinstated the commanded observance of the Passover, which the people were not keeping to any significant degree, if at all.
However, these well-meaning reforms also contained a subtle change: Under both Hezekiah and Josiah—at the king's command rather than God's—the people observed the Passover at the Temple rather than in individual homes (II Chronicles 30 and 35). The kings may have done this to ensure that the people actually kept the Passover, and did so without mixing in the Baalism that was so prevalent in the land. These kings' examples introduced a second way of observing the Passover. Now the Jews had both God's original Passover instructions as well as the kings' reforms to draw on when determining how to observe the festival.
While God intended the Passover and Feast of Unleavened Bread to be separate (though adjacent) observances, the Jews ended up combining the two during the Babylonian exile, as the Encyclopaedia Judaica confirms: "The feast of Passover consists of two parts: The Passover ceremony and the Feast of Unleavened Bread. Originally, both parts existed separately; but at the beginning of the [Babylonian] exile they were combined" (vol. 13, p. 169). This careless and unscriptural merging of festivals resulted in the Jews observing Passover late on Abib 14, just hours before the Feast of Unleavened Bread began. Thus, a third variation of Passover observance was added to the mix.
At the time of Jesus Christ, this mixture was on full display. Philo of Alexandria, in De Vita Mosis, notes that in the early first century, the Passover was not strictly a Temple-kept event, but one in which people also killed their own lambs without help from the priests. In his Wars of the Jews, Flavius Josephus records that in 4 BC over 250,000 lambs were sacrificed for Passover. However, given the limited space of the Temple environs and the fact that Jewish tradition (not the Word of God) held that the lambs were to be slain within a two-hour time slot (from the ninth to the eleventh hour, or 3:00-5:00 pm), it is readily apparent that not all of those lambs could have been sacrificed at the Temple. In fact, Joachim Jeremias, in Jerusalem in the Times of Jesus, calculates that the three courses of priests on duty could slay only 18,000 lambs during those two hours. Josephus records that the rest of the lambs—a far greater number—were slain by individuals at their own homes.
Another critical point is that, despite Passover and the Feast of Unleavened Bread being distinct festivals, they were commonly grouped together and simply called "Passover." Thus, when the gospel writers mention "Passover," it can sometimes refer to the Passover sacrifice itself (Matthew 26:17; Mark 14:12), the day when the sacrifice was made (Mark 14:1), or the whole eight-day period of Abib 14-21 (Passover plus Unleavened Bread; Luke 22:1).
In actuality, then, there were really two Passover observances happening at the time of Jesus: one led by the priests at the Temple and the other observed by the people in their homes. These separate observances were also at different times: The Temple-kept Passover was observed late in the afternoon of Abib 14, while the home-kept Passover was kept at the beginning of Abib 14. As the gospels show, Jesus and His disciples ate the Passover in a home rather than at the Temple, observing it the evening before the priests did at the Temple. In other words, Jesus kept it as Abib 14 began, while the priests kept it as Abib 14 ended.
David C. Grabbe