Thank you for contacting BibleAsk.
The Passover is a Biblical Jewish holiday. The Israelites commemorated their deliverance by God from slavery in ancient Egypt under the leadership of Moses. Thus, the Passover celebrates the story of the Exodus. According to standard biblical chronology, this freedom took place at about 1300 BCE (AM 2450).
The Israelites were instructed to mark the doorposts of their homes with the blood of a slaughtered spring lamb and, upon seeing this, the spirit of the Lord knew to pass over the first-born in these homes, hence the English name of the holiday.
The Israelites held the feast of Passover on the 14th of Nisan. They slayed the paschal lamb in the afternoon and ate it with unleavened bread, after sunset that same night, during the first hours of Nisan 15 (Ex. 12:6–14, 29, 33, 42, 51; 13:3–7; Num. 9:1–5; 33:3; Deut. 16:1–7
Nisan 15, a ceremonial sabbath, also marked the beginning of the Feast of Unleavened Bread (Ex. 12:8, 18, 34, 39; Lev. 23:5, 6; Num. 28:16, 17; Deut. 16:3, 4, 8). The feast activity continued through the 21st, the 15th and 21st of Nisan being celebrated as sabbaths irrespective of the days of the week on which they might fall (Exodus 12:16; Leviticus 23:6, 7).
On Nisan 16, the second day of this feast, the wave sheaf of the first fruits was offered in the Temple (Lev. 23:10–14). The term “Passover” was first used to point only to Nisan 14, but during the period of Christ it was sometimes used of the Feast of Unleavened Bread also (Luke 22:7; Act 12:3,4)(Antiquities ii. 14. 6; xi. 4. 8; xiv. 2. 1 [311–313; 109–111; 21]; xvii. 9. 3; War ii. 1. 3; v. 3. 1 [10; 99]). The services of the 14th to the 16th day of the feast were regarded as the most important.
On the 17th, those who had come up to Jerusalem to attend the feast were allowed to return to their homes if they want to do so. However, the devout among the Israelites kept the requirements of the ceremonial law and remained for the period of the whole feast rather than only for the least time obligatory by the rabbis.
In His service,