"The Christian is simply a Jew of the 'reformed' confession."
- Friedrich Nietzsche, The Antichrist (1888)
http://www.gutenberg.org/etext/19322
Maybe this is a reason or the only reason why his writings and ideology are highly recommended for anyone interested in theology and/or philosophy. In both, the philosopher was clearly trying understand and explain the social phenomenon that we know as religion (especially Judaism, Christianity & Islam) while pointing out the errors and lies in religious practices and/or beliefs.
In the quote above, he pointed out that Christianity has its roots in Judaism (same as Islam). In other words, Christianity is a mix of Judaism and the teachings that Jesus left us.
Said the latter, the differences between the three religions of Abraham (Judaism, Christianity & Islam) are similar. What he didn't explain is why followers of one religion sometimes fight with members of the others. Maybe it's mere sibling rivalry.
Anyway philosophy (especially that of Nietzsche) is exciting and fun even when it offends us or simply makes fun of us. It forces us to think and reevaluate our core beliefs and principles, which is important if we're to dare calling ourselves "real" Christians. In conclusion, Nietzsche, the biggest critic and enemy of religion, is perhaps the best professor of religion.
