The original Day of Pentecost was harvest thanksgiving day, an important occasion in the Jewish calendar. For almost twenty centuries it has also meant a very great deal to the Christian churches.
From the resurrection of Christ Jesus to Pentecost, there were but fifty days. It would seem that in this period the disciples grew remarkably in their understanding of what Jesus had actually achieved.
Still, it is indicative of the disciples' somewhat earthbound level of thought that they asked him before his ascension, "Lord, wilt thou at this time restore again the kingdom to Israel?"Acts 1:6. But Jesus turned their thought once again to the kingdom not of this world, to a far higher sense of his mission and their own. "And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power. But ye shall receive power, after that the Holy Ghost is come upon you."Acts 1:7, 8. And Jesus promised they would bear witness of him.