Has the Gospel Been Corrupted? Part 1- Christian Questions

So much of what Jesus taught was about the practical parts of living – learning to love, forgive and encourage one another - and these are the parts of his teachings that seem to garner the most attention. Jesus did, however, spend significant time imparting prophetic teaching as well.  He came to earth as a man to ransom the human race, and in so doing, to call out "a people for his name."  Much of his prophetic teaching was focused on how that calling would work and what that calling would face by way of challenges and pitfalls.  Jesus was specific about what to expect regarding that calling regarding Christianity in terms of corruption and deceit.  It sounds odd to think about Jesus calling out some future failures of what would come to be thought of as the Christian world, but he did.  How did he do it?  What did he say?  What did he mean?  What should we be paying attention to?