When carlisle told edward remember who you are what does that mean and why did carlisle say that?

I believe that Carlisle meant to reinforce the fact that Edward was a vegetarian vampire who loved Bella and, he said this aloud so Edward so that he would stop sucking Bella's blood, because he very well could have killed her. This may or may not be true, but it is my personal opinion of why he said this, and what it means.