Prior to Jesus's resurrection, the followers of Jesus appeared to be lacking in knowledge, easily frightened and quick to renounce Him (Peter), and generally unwilling to stand up for what they believed. Suddenly, after Jesus's ascension, Christianity explodes over the ancient world, believers are leaving their homes and belongings and going to every part of the world. I believe this was due to 3 factors: #1) Epiphany; the coming of the Holy Spirit to dwell bodily in those who believed Jesus (not something that previously occurred before Jesus's resurrection), #2) Personal witnessing of Jesus alive (Thomas), and of His ascension, and #3) witnessing of resurrected saints, some of whom people may have known, walking and speaking in Jerusalem shortly after Jesus's resurrection. These 3 events may have made it impossible for believers who were 'on the fence' to deny Jesus's power any longer. They witnessed Jesus's death, they witnessed His resurrection, and they witnessed other people that they knew for sure had died, has seen buried, and had been dead for months or years, and then saw them alive again. It's one thing to hear testimony that someone has risen from the dead, it's another thing to see it with your own eyes, particularly someone who you know, and saw buried. So they lost all fear of death, or of persecution, or of being rejected by their peers, or families, because they had first-hand knowledge that caused them to believe that they would live forever, in paradise. Whatever happened, it divided ancient Israel, and made it practically ungovernable for the Romans. As Jesus said, I come not to bring peace, but a sword; people were divided against each other fanatically, and the issue that divided them was the identity of Jesus. Anyway, in 72 AD Titus and the Roman Legion had to march on Jerusalem, and burn the temple down, and kill a third of the Jews, and cart the rest of them off to Germania (and Poland, same district in those days), where they lived as refugees and outcasts until they were collected together by Hitler, underwent the Holocaust, and then were returned to their promised land, just as foretold in the Old Testament.