A christian is a person living a life like Christ lived.
Anybody that claims to be a christian and is not living a life like Christ did is a liar and the truth is not in him/her.
then all christians are liars.
Which gets us back to the all have sinned....forgiven through Divine Grace argument. Perhaps we can reword it into Anybody that claims to be a Christian and is not trying their best to live a life like Christ did is not worthy. Makes me wonder about myself sometimes....