Christians claim that the majority of the disciples were martyred for their belief in the resurrection. They were tortured and killed in horrible ways, supposedly for their beliefs. And who would go through that for a lie?
Tracie Harris — Why Martyrs? [Atheist Experience Blog]
Were the Disciples Martyred? [EhrmanBlog]
Easter Reflection [EhrmanBlog]
Paul’s Execution [MappingTheMartyrs]
Stephen’s Martyr Legend [Acts 6-7]