The answer is actually quite simple. Read the Gospel of John. Disregard all of the miracles, the claims of godhood and the other religious aspects if you want to and concentrate on Jesus' philosophy. He speaks it quite plainly, and that alone should provide you with the context needed to tell the true Christians from the false ones. The difference should become rather obvious to you when you observe their behavior.
"They should rename the team to the Washington Government Sucks. Put Obama on the helmet. Line the entire walls of the stadium with the actual text of the ACA.
Fix their home team score on the board to the debt clock, they can win every game 17,000,000,000,000 to 24. Losing team gets taxed by the IRS 100%, then droned."