Self-denial is not a work you do to get saved. Self-denial is the natural outflow of faith. If there is no self-denial in your life, then you can’t have any true assurance of faith.
Your physical birth brought you into this physical world. You and the world around you are tainted with sin. Your body and the earth are linked together–from the dust you came and to the dust you will return.
Your flesh body wants to stay alive. It wants to fight for what it needs and wants. If it has to, it will kill to get what it thinks it needs.
Naturally, our bodies desire the things of this earth. The things of this earth are what it is–it is one of the things of this earth. It will go no higher than this earth if left to itself.
The problem with the things of this earth, including your body, is that, according to John’s Revelation, “the first heaven and the first earth were passed away.” Later John says that “the former things are passed away.”
This is all passing away! It’s all vanity. But that is not the end. Christ came to redeem creation and to redeem humanity. So He says, “Behold, I make all things new.” The old will be done away with and the new heaven and new earth will take over.
There is another world coming, and it is the world we are to be living for now. The only way you know this world is passing away and that a new world is coming is because God said so. Faith comes by hearing and hearing by the word of God.
It is our faith that overcomes the world. By faith we look at the things that are not seen, for the things that are not seen are eternal. We walk by faith not by sight. We no longer live for things of this world. We deny ourselves the things of this world because they do not fit in with the life of faith.
Faith in Christ is not just believing a set of facts about what Christ did, but it’s seeing yourself as being dead, buried and raised up with Christ. Our old man has been crucified with its affections and lusts. The world is crucified unto me and I unto the world.
Faith is not proved by repeating words or being able to explain stuff from the Bible. Faith is demonstrated one way–by what you live for.
Self-denial is simply living for the world to come, rather than living for this temporal world that is passing away. If your self-denial isn’t doing this, then it’s not self-denial.