Anyone can claim Christianity as their religion, but a devout Christian is someone who “practices what they preach” so to speak. It is the same with any religion really. How many celebrities claim to be Kabalistic or Scientologists for a fashion statement? It is something I have heard referred to as being a “little c” christian instead of a “big C” Christian.
Christ said in Matthew 7:21, “Not everyone that saith unto me Lord, Lord’ shall enter into the kingdom of Heaven; but he that doeth the will of my Father which is in Heaven.” Here we see that there will be some professing christians (little c) that will stand before the Lord and Jesus will say they are condemned because they talked the talk but didn’t walk the walk.
The chapter goes on to say that they will try to get in on their works but will still be denied. “Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?’ And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.'” Notice the first word of the verse. “Many” will stand before God with their professed Christianity and will be denied. It makes me sad to hear but at the same time, I know it is true.
A Bible teacher in high school gave the best definition of Christianity I have heard to date. “Christianity is a personal relationship with the person of Jesus Christ.” There are many who are members of the Christian religion ( little c’s) but few who are of the Christian faith (big c’s) having a personal relationship with Jesus. They don’t do the works of the Father. They sit on the couch watching the game instead of going to church. They don’t help those around them. They don’t take time to read their Bible. However, at the first sign of crisis, they are Christians, begging God to help them in their time of need. They are those mentioned in II Timothy 3:5 who have a form of godliness but deny the power thereof and the verse commands us to turn away from these people.
In short, a christian (little c) is someone who adheres to the principles of the Christian faith, while a Christian (big C) is someone who has a relationship with Jesus Christ that compels them to do the work of the Father.