Season of Pentecost
Pentecost was originally an Old Testament festival, since the time of Josephus calculated as beginning on the fiftieth day after the beginning of Passover. In the Christian calendar, it falls on the seventh Sunday after Easter. It was called the Feast of Weeks (Shavuot), and in the Old Testament was originally an agricultural festival celebrating and giving thanks for the "first fruits" of the early spring harvest (Lev 23, Exod 23, 34).
By the early New Testament period, it had gradually lost its association with agriculture and became associated with the celebration of the creation of God’s people and their religious history. By the destruction of Jerusalem in AD 70, the festival focused exclusively on God’s gracious gift of Torah (the "Law") on Mount Sinai. It continues to be celebrated in this manner in modern Judaism.
The word “pentecost” means “fiftieth day.” In most Christian traditions, Pentecost Sunday occurs 50 days following Easter Sunday (counting Easter Sunday since it is the first day of the week). Those 50 days span seven Sundays after Easter, so Pentecost is the seventh Sunday after Easter (7 weeks times 7 days = 49 days, plus Pentecost Sunday). Since Easter is a “movable feast,” meaning that it occurs on different days in different years (it is tied to the lunar cycle while the calendar is solar based), Pentecost is also moveable. It can occur as early as May 10 and as late as June 13 (see The Church Year for current dates). Some Christian traditions, Eastern Orthodox for example, use a different religious calendar and so have different dates for much of the Christian Year.
The sanctuary color for Pentecost Sunday is red, the color of the church. Technically, red is used only for the Sunday of Pentecost, although some churches use red for the Sundays between Easter and Pentecost Sunday. The red symbolizes both the fire of Pentecost as well as the apostles and early followers of Jesus who were gathered in the Upper Room for the empowerment from God to proclaim the Gospel throughout the world.
For Christians, Pentecost Sunday is a day to celebrate hope, a hope evoked by the knowledge that God, through the Holy Spirit is at work among God's people. It is a celebration of newness, of recreation, of renewal of purpose, mission, and calling as God’s people. It is a celebration of God’s ongoing work in the world. Yet, it is also a recognition that God's work is done through God's people as the Holy Spirit pours God's grace upon them.