What defines you? Is what you do, the thing that defines you? Is what you put your faith in, the thing that defines you? Are the relationships with people that surround you what defines you?
I dont know that these things can be answered direclty and especially without much debate, but I do know this, that without Jesus I can do nothing (Phillipians 4:13), whithout faith in Jesus I have not real faith (Romans 10:17), and without a right relationship with Jesus I have no relationship at all (Matthew 22:37).
In his Grip