The Bible does not attempt to differentiate between the terms Christian and disciple. These terms are used interchangeably to refer to the followers of Jesus. Even the early church fathers like Paul, Peter, John, and their lives did not attempt to differentiate them because these terms were the same.
The question about whether you can be a Christian and not a disciple is as though you asked whether someone can be a man and not a male. Impossible! All things being equal, a man is automatically a male. A Christian should automatically be a disciple; the two are not separable. If you meet a Christian who does not merit being called a disciple of Jesus, then he is not a Christian at all.
Over the centuries, it has been easy for people to hide behind the name Christian. They would say, “I am a Christian”; but they would hardly say, “I am a disciple of Jesus”. If a professing Christian would almost not call himself a disciple of Jesus or is doubtful and finds it difficult to call himself a disciple of Jesus, then he is a witness to himself that he is a liar and does not belong to any of the two. Such difficulties arise when one’s deeds are not in line with the word of God.
The proclamation ‘I am a disciple of Jesus’ is a statement that arouses public attention and scrutiny. Any who makes such a proclamation immediately comes under public scrutiny; they begin to examine his life, weigh his deeds, and pass all the pieces of his life through the righteousness filter to ascertain whether his claims are true. If his claims are true, people will testify to them; if they are not, people will immediately take him for a liar.
‘Christian’ has become a light word, anyone who happens to be affiliated with a church, whether he attends church regularly or not, or whether he is living by God’s word or not, calls himself a Christian. Just any hypocrite, backslider, and mere churchgoer can hide behind the term Christian. Honestly, it would be hard for many so-called Christians of today to say boldly that they are disciples of Jesus Christ. This is because their deeds give them up; they fail to lead an exemplary life that is a true reflection of Jesus’ life.