"You will receive power when the Holy Spirit has come upon you" (Acts 1:8) has been a key text for Pentecostalism

Pentecostalism takes its name from Pentecost, at which time Jesus' followers received the Holy Spirit (Acts 2:1-4). By virtue of its emphasis on conversion, Pentecostalism is part of evangelicalism; Pentecostalism's distinctiveness lies in its emphasis on speaking in tongues, healing, and other manifest gifts of the Holy Spirit. Pentecostalism has roots in the Methodist movement, which prized holiness or sanctification, and in African-American churches which prized spontaneity, participation, and inspired leadership. Since the Azusa street revival, Pentecostalism has has grown dramatically. The Assemblies of God and Churches of God in Christ are perhaps the best-known Pentecostal denominations, though the movement extends to many independent congregations. In the Charismatic movement, Pentecostalism began to penetrate Roman Catholicism and the mainline Protestant churches. Pentecostalism has grown very rapidly in Latin America and Africa and some parts of Asia; the largest Pentecostal congregation is in Korea. Pentecostalism plays a large role in Christian growth: by the year 2000, there were an estimated 250 million Pentecostals worldwide, the second largest expression of Christianity after Roman Catholicism.