Leviticus 23:4 These are the feasts of the Lord, even holy convocations, which ye shall proclaim in their seasons. 5 In the fourteenth day of the first month at even is the Lord's Passover. 6 And on the fifteenth day of the same month is the feast of unleavened bread unto the Lord: seven days ye must eat unleavened bread.
[Patriarchs & Prophets pp 537] There were three annual assemblies of all Israel for worship at the sanctuary. Exodus 23:14-16. Shiloh was for a time the place of these gatherings; but Jerusalem afterward became the center of the nation's worship, and here the tribes convened for the solemn feasts. The people were surrounded by fierce, warlike tribes, that were eager to seize upon their lands; yet three times every year all the able-bodied men and all the people who could make the journey were directed to leave their homes and repair to the place of assembly, near the center of the land. What was to hinder their enemies from sweeping down upon those unprotected households, to lay them waste with fire and sword?
What was to prevent an invasion of the land, that would bring Israel into captivity to some foreign foe? God had promised to be the protector of His people. “The angel of Jehovah encampeth round about them that fear Him, and delivereth them.” Psalm 34:7 [A.R.V.]. While the Israelites went up to worship, divine power would place a restraint upon their enemies. God's promise was, “I will cast out the nations before thee, and enlarge thy borders: neither shall any man desire thy land, when thou shalt go up to appear before the Lord thy God thrice in the year.” Exodus 34:24.
The first of these festivals, the Passover, the feast of unleavened bread, occurred in Abib, the first month of the Jewish year, corresponding to the last of March and the beginning of April. The cold of winter was past, the latter rain had ended, and all nature rejoiced in the freshness and beauty of the springtime. The grass was green on the hills and valleys, and wild flowers everywhere brightened the fields. The moon, now approaching the full, made the evenings delightful.
Leviticus 23:37 These are the feasts of the Lord, which ye shall proclaim to be holy convocations, to offer an offering made by fire unto the Lord, a burnt offering, and a meat offering, a sacrifice, and drink offerings, every thing upon his day.
May God add His blessing to the study of His word. "Good night" and God bless!