Michael Horton, Christless Christianity
It's very easy to make Christianity a list of do's and don't's that should be done to make your life run more smoothly, or to give you purpose. It's very easy to skip over man's sin and instead focus on our own abilities and personal achievements. But that's not Christianity, and it's certainly not the gospel. True gospel is a stumbling block, a "rock of offense". And in our efforts to remove the offensive part of Christianity, we've removed the most pivotal part, Christ himself.
Below is my favorite song by Christian artist Michael Card. Although the song was written in the 1980's, I think the message is still true today.