Originally, God's instructions stipulated that Passover was to be observed on Abib 14 in individual homes, with the blood of the lamb caught in a basin and smeared on the doorposts and lintel. However, during the reigns of zealous kings like Hezekiah and Josiah, reforms were instituted to bring Judah back to God's way, including observing Passover at the Temple rather than in homes, introducing a second way of keeping the festival. At the time of Jesus Christ, this resulted in two distinct Passover observances: one at the Temple, led by priests late in the afternoon of Abib 14, and another in homes at the beginning of Abib 14. Jesus and His disciples ate the Passover in a home, observing it as Abib 14 began, while the priests kept it as Abib 14 ended. Despite the limited space of the Temple and the short time slot for sacrifices, historical records indicate that far more lambs were slain by individuals at home than by priests at the Temple.

During the reigns of Hezekiah and Josiah, strong and righteous kings of Judah, the observance of Passover underwent significant changes from God's original commands. These Passovers, held at the Temple, marked a departure from the domestic sacrifices described in earlier scriptures. The kings personally supervised these Temple-centered Passovers to prevent a return to pagan practices, enforcing obedience due to the people's deep-rooted idolatry. Alongside the Passover lamb, numerous other sacrifices from flocks and herds, such as burnt, peace, and thank offerings, were made during the Days of Unleavened Bread, reflecting administrative decisions under unusual circumstances. Despite this deviation, God accepted these observances, though not as a replacement of His initial intent for a home-killed Passover. This acceptance stemmed from the hardness of heart among the people, making a Temple-centered celebration preferable to none at all under such extreme religious perversion. Historical accounts from the time of Christ indicate that many Jews still sacrificed the Passover lamb at home, adhering to God's original command for a domestic observance, while a smaller group, primarily religious leaders controlling the Temple, followed the pattern of Temple sacrifices. This resulted in two distinct Passover celebrations, highlighting a divergence in practice. The Temple sacrifices, often termed Passover offerings, included cattle and other animals not specified for the Passover lamb, which were offered during the Feast of Unleavened Bread, further distinguishing them from the original Passover command.

During the lifetime of Jesus Christ, the Jews observed Passover in two distinct ways. One was kept by the people in their homes in the evening as Abib 14 began. The other, led by the priests, was observed at the Temple in the late afternoon of Abib 14. While most people sacrificed lambs throughout the city as Abib 14 approached, the priests would not slay the Temple Passover lambs until the following afternoon.

The practice of sacrificing Passover lambs at the Temple emerged as a significant change influenced by historical figures like Hezekiah, Josiah, and Ezra, who centralized worship to control religious observances and prevent the people from straying from God's law. This shift moved the sacrifice from homes to the Temple, a change not originally commanded by God. Historical records, such as those from Josephus in "Wars of the Jews," describe the vast numbers of people participating in Passover at Jerusalem, highlighting the scale of Temple sacrifices during this period. Despite these large gatherings, the centralization represented a departure from the original instructions given in Exodus 12, Leviticus 23, and Numbers 9, which Jesus Christ adhered to by keeping Passover at the beginning of the 14th day, not following the later Temple-based tradition. The New Testament accounts, including John 13:1, clearly distinguish that Jesus observed Passover according to God's original command, not aligning with the Jewish practice of a Temple-sacrificed lamb on a different day. This adherence underscores that the authority to alter God's commandments was never granted to human leaders, regardless of their intentions.

Passover, as originally instituted, occurred at the beginning of the fourteenth day, with the lamb being killed at home and its blood sprinkled on the doorposts. The entire day was devoted to preparations, including slaying, cleaning, and roasting the lamb, staying in houses through the night of the Death Angel, burning the remains, and gathering for departure during the daylight portion of the fourteenth. God demands work on this day in preparation for the feast that follows, marking the memorial of coming out of sin at sunset of the fourteenth into the fifteenth. This domestic observance set the pattern for all Passovers until changes occurred. Later, a shift is noted where proponents of a fifteenth Passover claim that after the original domestic celebration, lambs were sacrificed at the tabernacle or temple, with blood sprinkled on the base of the brazen altar instead of doorposts. This change is questioned, as no clear command from God is found in His Book to transition from domestic to temple sacrifices for Passover. Even after the establishment of the tabernacle and priesthood, as detailed in Exodus and Numbers, God did not alter the original instructions for Passover, maintaining it as a domestic observance without a specified temple sacrifice or holy convocation. Historical accounts from scholars like Philo, a contemporary of the time of Jesus Christ, highlight that Passover was distinct from other sacrifices, uniquely observed outside the temple context. Contrasts between the original and traditional practices show significant differences: the original lamb was killed at the beginning of the fourteenth at home, eaten on the night of the fourteenth, with blood on doorposts, commemorating Passover over eight days including Unleavened Bread; the traditional practice involved killing the lamb at the end of the fourteenth at the temple, eating it on the night of the fifteenth, with blood on the altar, commemorating the Exodus over seven days incorrectly termed as Passover. These alterations reflect major changes in the observance and meaning of Passover and Unleavened Bread.