Anyone can claim to be a "Christian" these days because the word Christian can mean whatever one wants it to mean. But the Bible provides an objective definition of what a true follower of Christ is. And so, what is a Biblical Christian, that is, a Christian according to Biblical definition?
A Biblical Christian is someone who has repented of their sin against God and trusted in Jesus Christ alone for salvation from the condemnatory punishment of God over sin. Repentance means turning away from sin in full surrender to the Lordship of Jesus Christ, while faith in Him means trusting in His substitutionary sacrifice on the cross, that it has wiped out your sin-debt against God in complete forgiveness. True faith is a repentant faith, and true repentance is a believing repentance. To be a Biblical Christian, Jesus must not only be your Saviour... He must also be Lord over your life. He said, "If anyone would come after Me, he must deny himself, take up his cross, and follow Me." Following Jesus means complete denial of yourself; taking up your cross means following Jesus even to the point of death; and following Jesus means giving up your autonomy to obey Him in everything.