Many people today think a Christian is someone who accepts that there is a God, who tries to live a good life or who goes to church. But none of these by themselves, or even all together, make a person a Christian.
The Bible is the one authoritative source of knowledge about God. It is the very word of God himself and states its purpose like this: "these things are written that you may believe Jesus is the Christ, the Son of God, and that by believing you may have life in His name" (John 20:31)