But the Bible records history and so is, at least in principle, verifiable. When the events recorded in the Bible are corroborated by history, it gives them a far greater degree of credibility, they cannot simply be ignored. However a short time later his followers were proclaiming that he had come back to life. Jesus' closest followers would have seen him die. They knew if they were telling the truth or not.
Objectors say that the same argument can be applied to the spread of other religions.
But it can't. The spread of Buddhism means that the early Buddhists were convinced that the Buddha had found the way to enlightenment. The spread of Islam means that the earliest Muslims were convinced that Mohammad was a prophet of God. But the earliest Christians claimed something far more extraordinary. They were convinced, and often staked their lives on it, that Jesus had risen from the dead.