Don't underestimate the pull of the world. Some may, like Samson, already be entrapped by it and don't even know it. That is the worst entrapment--when you can take the Lord's supper every Sunday and live like the world the rest of the week.
The Bible says that Demas forsook his faith for the love of the world (II Tim 4:10.) James says friendship with the world is enmity to God. WOW!!! The world has a way of compromising our faith in so many, many subtle ways. The Bible says that Satan is the prince of this world. He tried to bribe Christ to worship him by offering him all its kingdoms. Jesus knew that though you gained the entire world it would all be eventually lost because the world and all that is in it passes away. We brought nothing into this world it is it certain that we will take nothing out of it.
Therefore, the passage about Demas departing for the world should not be read over too casually. We should think seriously that that which wrecked Demas' discipleship could absolutely do the same for us. If you say, "not I," I would have you to recall that is exactly what Peter said about his denying Christ - but when circumstances developed around him that he had no idea could and would suddenly come about, he did - and three times in rapid succession--one was with an oath. Many once in the Amen corner - I could name some--have now gone to the devil.
What is there then that can cause one to act like Demas by just walking away from salvation for the call of the world. Not any one thing but it is surely anything that we allow to choke the thrill, adventure and life of Christ out of me. It can be a multitude of little things that seem absolutely harmless at first but they slowly entangle my soul and gradually sap the energy of living for Christ out of me. These besetting things can vary from one individual to another but each of us knows his own weaknesses. It is when we stop confessing them as weaknesses and no longer resist them that we are in deep trouble. Peter said it affects a person's memory causing him to forget the moment he was saved. He forgets also that his citizenship is in heaven.
So don't pass over this sad statement about Demas too quickly. We all are vulnerable. That is why Paul warns us all: "Let him who thinks he stands take heed lest he fall." I would say that we all have fallen at some time or another and are now here by the grace of God; "for all have sinned and come short of the grace of God" Just as Peter, let's let that be a lesson to us and stand firm for Christ. AMEN