In ancient Israel, Shavuot was a joyful harvest festival. Worshipers brought offerings from the produce God had given them.
During the Temple period, pilgrims traveled to Jerusalem. Firstfruits were brought as an expression of thanksgiving. Grain offerings and animal sacrifices were also part of the festival worship.
Deuteronomy describes the celebration as something to be shared. Families rejoiced together with servants and Levites. Foreigners, widows and orphans were also included.
This made Shavuot more than a private act of thanksgiving. The community celebrated God's provision together.
By the first century, Jerusalem could draw large numbers of Jewish pilgrims for the festival. This provides the setting for the gathering described in Acts 2.