Os Guinness talks about differences between Christianity and other religions in an interview with Justin Brierley a few years ago. He made a statement that Christianity is the only “traveling religion”.
He observed that Hinduism began in India and remains primarily in India. Buddhism began in India and remains primarily in India and Eastern Asia. Islam began in the Middle East and remains primarily in the Middle East. Christianity, however, began in the Middle East. Then it moved to Europe; and then it moved to North America; and now Christianity is growing fastest in Africa and Latin America and Asia.
While I think Guinness overstates the case little bit, he got me thinking about the how the major world religions have spread. For instance, Islam, which rivals Christianity in numbers, grew very rapidly during the life and immediately after the death of Muhammad. It spread throughout the centuries into Europe and down into Africa and more recently across Southern Asia.
To that extent, Islam rivals Christianity in its “travel” around the world. But the spread of Islam looked different than the spread of Christianity. This is the significant fact, in my opinion – not so much that Christianity has traveled through all the world (though it has) like no other religion.