13Now listen, you who say, "Today or tomorrow we will go to this or that city, spend a year there, carry on business and make money." 14Why, you do not even know what will happen tomorrow. What is your life? You are a mist that appears for a little while and then vanishes. 15Instead, you ought to say, "If it is the Lord's will, we will live and do this or that." 16As it is, you boast and brag. All such boasting is evil. 17Anyone, then, who knows the good he ought to do and doesn't do it, sins.
We talk a lot with people who are not believers. It is easy to identify some personal sins they have committed. Who hasn't lied, stolen, blasphemed or lusted? What do you do with a person who claims to already be a Christian? How about if they admit their sin, and say that they are a Christian, but something seems to be missing?
James is a great book about Christian living. Not about how to become a Christian, but how to act like one. When I meet someone who says they are a Christian, I take them through the Law just like anyone else. If someone tries to justify their sin, or minimize it, rather than admit it, it raises a red flag for me. Then I ask if they read their bible daily. Someone who can't remember when they last picked up their bible also raises my suspicions. Finally, if someone has definitely repented and put their faith in the Savior, I ask them if they are regularly sharing their faith verbally, at least with people they know, if not necessarily with outright strangers.
"Have you no wish for others to be saved? Then you are not saved yourself. Be sure of that." - Charles Spurgeon