Self-denial is necessary in avoiding sin to which we are inclined and which we find give us pleasure.
But it is necessary also, when no sin or temptation is present, to preserve that frame of mind which keeps us in readiness for temptation and enables us to resist it when it does come.
A constant habit of self-denial is necessary to make us proof against the gradual and unperceived approach of sin either in the form of coldness and distaste for religion, or sloth, or a desire to gratify the flesh. So Paul (I. Cor. ix., 27) said he kept his body under and brought it into subjection, lest even he, through the deceitfulness of sin, should become a castaway.
It follows that self-denial is absolutely necessary to growing in grace. We are mistaken if we imagine we are growing in grace, when we are practicing no self-denial. Jesus said (Luke ix., 23): "If any man will come after Me let him deny himself and take up his cross daily." Now what does that word "daily" mean in this connection? Indeed growth in piety is a growing out of self so that self is crucified, as Paul says he was.
Self-denial must be practiced then.
1. In abstaining from sins of all kinds.
2. In performing all our duties of religion, however hard and unpleasant they may be, as attending all church services, ordinances, etc., and giving according to your ability.
3. In practicing private prayer however hard and distasteful it may be at first. Some men have prayed three hours a day in secret, as, for example, Luther.
4. In abstinence from food, i.e., fasting; and sometimes from sleep when it is necessary to have time to pray, etc.
Get the upper hand of your animal nature and keep it by daily self-denial and you will mount up with wings as eagles, you will run and not be weary, you will walk and not faint.