It's How You Finish
Then Jesus explained: "My nourishment comes from doing the will of God, who sent me, and from finishing his work."- John 4:34
G. K. Chesterton said, "Christianity has not been tried and found wanting. It has been found difficult and not tried." If someone says they have tried Christianity and it didn't work for them, it is because they never had a true encounter with the living God. I believe any person who has really met Jesus Christ will continue to grow spiritually.
Sometimes we wonder about people who seem to have responded to the gospel but then fall away. I would suggest that if they truly were believers, they never would have left. Having said that, it is possible to be a true believer and go astray. If you are a believer, you always will come home again. But if you never were a believer, you won't. The Bible says, "A pig returns to its sloth and a dog returns to its own vomit." A pig goes back to his element; he never changes. But if you are a prodigal, then you will always return home again.
Sometimes people start off with great enthusiasm and don't finish what they have begun. And sometimes people start off weak, but they get stronger with the passing of time. We see this in the life of Nicodemus, who was a religious leader and national celebrity in Jesus' day. John 3 tells us that he came to Jesus at night, asking questions. We don't know whether he believed at that point. But when Jesus was crucified, it was Nicodemus who stepped forward, along with Joseph of Arimathea, to claim the body of Jesus. The point is that Nicodemus ended well.
Some have a feeble beginning, but a strong finish. But that is better than having a strong beginning and no finish at all. So it is not how you start out-It is how you end!