If you had been living in that time and place where the itinerant healer and preacher was crucified, would you have been able to foresee that his teachings would be remembered 2,000 years later? How likely would it have seemed to you that from a small bunch of scared followers, a world-wide religion would develop?
How did it happen?
A clue is in this passage from Acts. After his resurrection, Jesus appeared to the disciples he had chosen to be his apostles. He told them that they were going to be empowered by the Holy Spirit to be witnesses to the ends of the earth.