Leviticus 23 organizes Israel's year around the set feasts of Yahweh, even holy convocations, which you shall proclaim in their appointed seasons. The list begins with the weekly Sabbath, a day of complete rest. Time itself belonged to God, and these gatherings kept His saving acts at the center of Israel's memory.
The spring feasts began with Passover on the fourteenth day of the first month, followed by seven days of Unleavened Bread. When they first reaped the harvest, the priest waved the sheaf before Yahweh on the day after the Sabbath. Then they counted seven Sabbaths, fifty days, to the Feast of Weeks, when new grain was offered. In the middle of the harvest laws, God repeats the command to leave the corners of the fields for the poor and the foreigner.
The fall feasts came in the seventh month. There was a memorial of blowing trumpets on the first day, the Day of Atonement on the tenth, and the Feast of Booths beginning on the fifteenth. For seven days Israel lived in booths, that your generations may know that I made the children of Israel to dwell in booths when I brought them out of the land of Egypt. The New Testament connects several feasts to Christ. He is our Passover (1 Corinthians 5:7), raised as the firstfruits of those who have died (1 Corinthians 15:20), and the Spirit was given on the day of Pentecost (Acts 2:1).