When the Day of Pentecost Came by Mark A Hewitt, Pastel & Pen, 26 May 2012.
Ten days after the ascension of Christ and fifty days after his resurrection, the Holy Spirit descended on the disciples on the day of Pentecost. Pentecost was an established Jewish festival also known as the Feast of Weeks, which drew people from many nations back to Jerusalem (Lev. 23:15-21; Deut. 16:16). Pentecost symbolizes a new beginning. It celebrates the unleashing of the Holy Spirit on the world and the empowering of the church to reach the world with the gospel. In celebrating Pentecost, the church expresses its gratitude for the faithfulness of Christ in fulfilling his promise to send “another counselor” (John 14:16); celebrates the work of the Spirit in renewing all of creation; professes its confidence and security in knowing the Spirit’s power is available for its
mission; and grows in awareness of the immensity of its calling to reach the world with the gospel. The traditional color for Pentecost is red, after the flames described in Acts 2:3.
From: The Worship Resource Book, Page 693