What does it mean to be a Christian? I've seen handouts that say it is a four step process.
1. recognize that you're a sinner
2. recognize that your sin makes you imperfect, unable to go to heaven
3. recognize that Christ died to cover your imperfection
4. accepting Jesus's sacrifice
I've heard the illustration that faith is like sitting in a chair. A person can have faith that a chair will hold them, but until they sit in the chair they haven't acted on their faith.
I don't feel like Christianity can be summed up by a process or a metaphor. There are hundreds of colleges and universities dedicated to the study of Christianity. My Bible has 1440 pages in it. I have considered myself to be a Christian for about 7 years. Understanding what Christianity is is a process that continues for me everyday. Christianity is a relationship. Its about a human falling in love with their creator. It is so much more than saying a prayer or getting dipped in water. When Jesus talks about salvation, he doesn't lay out a four step process, he tells people to love him and follow him. To sell their things and give to the poor, an act of selflessness. Jesus talks to Nicodemus about being reborn, leaving his old life to live to glorify God. A friend once asked me what it meant to be a Christian and it was such a hard question that I never really gave him an answer. Being a Christian means having a relationship so strong that you no longer can make decisions on your own, you have to consult God. It means giving up your life for the glory of God. God told Moses that he is "I Am" because God is so far outside of our understanding that "I Am" is the only way to come close to describing him in our language.