What's the Diff?

I was chatting with my friend Richard the other day. He had introduced me to two actors he knew when went to see a play last week, and we had brought the youth group along. Our dicussion with these two people turned to Christianity and they expressed that they had given their hearts to God with the past year or so and were now reading various books to grow in their faith.

I was commenting to Richard afterwards that it was cool that they were Christian, and he agreed. Until then, though, he hadn't known they were Christian even though he had spoken to them before.

He commented that he finds it tricky to really determine if someone is a Christian, though many people would claim it. Case in point, he works with a lot of homeless youth in his job. When a conversation turns to Christianity, he has heard several kids immediately spout all of the right words and profess to be Christians. And yet, these same kids will profess other beliefs at other times. What's the difference between the actors and the homeless youth, each professing to be Christian?

I have some acquaintances who would strongly profess Christianity and yet they have not attended church regularly in several years. I have other acquaintances that profess Christianity while living common-law with their boyfriend/girlfriend. I knew a lady that had always been actively involved in church, but she eventually decided that she had to concentrate on her career so she stopped attending church and promised that she would 'get back into it' once she retired and had more time. I know of other people that fulfill the cliche of living like a Christian on Sunday and living like the devil the rest of the week.

So what's the difference? Would the real Christians please stand up?