Weeks marked an important point in the agricultural year and was one of the biblical pilgrimage festivals. Its Greek name, Pentecost, refers to the counting of fifty days.
The festival joined gratitude for harvest with worship before God.
The Torah connects Weeks with the grain harvest and offerings of firstfruits. Later Jewish tradition also associated the season with the giving of the Torah at Sinai, although the development of that association should be distinguished from the festival's explicit biblical agricultural setting.
For farming households the festival came during an important agricultural season. Pilgrims who traveled to Jerusalem had to interrupt normal work and undertake the journey to the Temple.
Agricultural installations, grain remains, roads, and Jerusalem's pilgrimage infrastructure provide material background for the harvest and travel associated with the festival.
Exodus, Leviticus, Numbers, and Deuteronomy describe the Feast of Weeks. Acts 2 places Jesus' followers in Jerusalem at Pentecost when the Holy Spirit came upon them.
Weeks celebrated God's provision in the harvest and required offerings from the produce of the land.
The Gospels do not emphasize Pentecost, but Acts continues the New Testament story by placing the coming of the Holy Spirit on this Jewish festival day.
Weeks was an established pilgrimage and agricultural festival during the Second Temple period.
The later strong identification of Pentecost with the giving of the Torah should not automatically be assumed to have had the same prominence among all Jews in Jesus' lifetime.
The Jewish setting of Pentecost explains why Jerusalem contained worshipers from many places when the events of Acts 2 occurred.