If somebody is not sure whether they're a Christian or not, in some sense, that's a good thing to ask themselves. Paul says in 2 Corinthians 13:5 to test yourselves and see whether or not you're in the faith. You look at John's first letter that he wrote, and he wrote that letter to help people gain the assurance of whether or not they are a follower of Christ or not.
Photo Credit: ©SWN Design