This is a different type of post than usual. I just want to recommend that you read The Mark of the Christian. It is a very quick read, but very profound. In this little treatise, Francis Schaeffer expounds Jesus' words in John 13.34-35. "A new command I give you: Love one another. As I have loved you, so you must love one another. By this all men will know that you are my disciples, if you love one another."
Dr. Schaeffer, in essence, says that the "mark of a Christian" is love of others. We have gotten away from this being our distinguishing mark as followers of Jesus. Although written in 1970, it is as true today as it has ever been.
I am currently reading John Woodbridge & Tim George's book The Mark of Jesus. In it, the authors refer often to Dr. Schaeffer's book. I want to post something on The Mark of Jesus early next week, but really feel that The Mark of the Christian is a good warm-up to it.
It is quite good, very thin, & on sale here.