The rapid growth of Pentecostalism since the beginning of the twentieth century raises the question whether this outpouring of the Holy Spirit might have been predicted in the Bible. The number of official members is still smaller among Pentecostals than Catholics; however, it is not unreasonable to suppose that Pentecostalism has more practicing members than the Catholic Church. In my view, there are two main reasons for this. First, Pentecost was the evening before the eighth day of God's working in this world. The Old Testament prophet Joel predicted this by prophesying about the former and the latter rains, with a time of drought in between. Second, the Catholic Church emerged in this time of drought. This is predicted in Book of Revelation through the woman in the wilderness who has twelve stars on her head, signaling the twelve Apostles who are conveying the Holy Spirit to her with the goal of endowing the bishops and priests, with the power of the Spirit. In what follows, I have listed the references I used to support the development I outline in this book. It is my hope that this will contribute to an ecumenical view Professionally I am a jurist and political economist, born 1936. I became a devout Christian with 23 years at Easter and therupon received the prayer of the tongue without knowing anything of the Pentecostalism. After reading the medieval mystics, I became a Catholic three years later and got there intensive private lessons a whole year. Later on I got aquainted with the charismatic renewal and got active there. Today I am going on Saturday in a Catholic mass and on Sunday in a Pentecostal community.