The Christian Church was born on the Day of Pentecost—fifty days after the last Passover celebrated by Christ Jesus. Continuously occupied in deep, unified prayer, the disciples had been waiting for the coming of the Holy Spirit, the Spirit of truth, promised them by their Master. They were expecting it, preparing for it. They were ready for it.
In the book of Acts it is recorded that the disciples "were all with one accord in one place. ... And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance." Acts 2:1, 4;
They were all at one in the unfoldment of the Christ, the divine, impartial impartation of the eternal truth of God and man. In that exalted moment the prophecy of Joel was fulfilled: "It shall come to pass afterward, that I will pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions." Joel 2:28;
