Sadly, the simple, almost painless, prophecy of Adam could not be fulfilled in its ideal form. All the world wondered after the power of sin as every imagination of their hearts was only evil continually. To save the human race, God preserved Noah and his family through a global flood. Yet, again, the world turned to its innate lust for power and pleasure in seeking to build a world empire around the tower of Babel. God dispersed the race, selected Abraham because of his faithfulness, and started a new plan based on saving one nation at a time.
The world was lost. It was now necessary for a person to “come out” of the world and into Abraham's family—the future nation of Israel. That nation was to be a shining example of the blessings that result from obeying God’s law of love. As other nations saw their happy, fruitful lifestyle, they would join with the Hebrew nation. Thus, the empire of Israel would conquer the world (or most of it) by peace. This Plan B was what prompted God to give Moses the annual calendar of feasts as a form of living prophecy.
4-8) Passover: 14th day, 1st month
9-14) Firstfruits: 16th day, 1st month
15-22) Feast of weeks (Pentecost): 12th day, 3rd month
23-25) Memorial of trumpets: 1st day, 7th month
26-32) Day of Atonement: 10th day, 7th month
33-43) Feast of tabernacles: 15th day, 7th month
1-5) Preparations
6-14) Bullock sacrificed for high priest
15-19) Goat sacrificed for the people
20-28) Scapegoat bears sin to wilderness
29-34) Happens on 10th day of 7th month
Lev 25:9-10) Jubilee trumpet blown that same day