Our fallen nature is prone to desires, which if followed, will lead to death of body and soul.

These are:

Pride, too great an admiration of oneself, the ultimate source of morality.
Avarice, a desire for wealth as the ultimate purpose of life.
Envy, sadness at another's good or joy at another's misfortune. Why, because I should have what another has.
Lust, an inordinate pleasure of the flesh or a shifting of the center of personality from the spirit to the flesh.
Anger, a violent desire to punish or a desire to get even.
Gluttony, excessive eating or drinking. "Do I live to eat or do I eat to live?"
Sloth, neglect of one's physical or spiritual duties. (e.g. I do not pray because it is unpleasant or boring.)

God's commandment are meant to counteract these tendencies which, if followed, can only lead to self-destruction. But, to continually fight even against one of these tendencies is painful as Sirach warns: "My son, when you come to serve the LORD, stand in justice and fear, prepare yourself for trials." (Sr. 2:1)

The only Son of God accepted his sufferings out of love for his Father and his love for us. He teaches us accept our inevitable sufferings as he did for the love of God, self and neighbor. Sufferings become sacrifices, that is, sacred acts or offerings made to God. Someone has well said,

"Sacrifice is the only language that love can speak and love is the only means of filling the human heart."

The modern individual who does not see suffering as sacrifice locates his higher purpose in the well-being his body and ego. The only way out is to seek medical treatment rather than offering pain as a sacrifice for the benefit of his soul. (Ariel Glucklich, Sacred Pain, Oxford University Press, Inc., 2001, p. 62)

4. The Pain of Loneliness