“THE ANOINTING OF THE SICK

“By the sacred anointing of the sick and the prayer of the priests the whole Church commends those who are ill to the suffering and glorified Lord, that he may raise them up and save them. And indeed she exhorts them to contribute to the good of the People of God by freely uniting themselves to the Passion and death of Christ.”
CCC 1499

ILLNESS IN HUMAN LIFE

“Illness and suffering have always been among the gravest problems confronted in human life. In illness, man experiences his powerlessness, his limitations, and his finitude. Every illness can make us glimpse death.

Illness can lead to anguish, self-absorption, sometimes even despair and revolt against God. It can also make a person more mature, helping him discern in his life what is not essential so that he can turn toward that which is. Very often illness provokes a search for God and a return to him.”
CCC 1500-1501

 “So they went out and preached that men should repent. And they cast out many demons, and anointed with oil many that were sick and healed them.” Mark 6:12-13

CHRIST THE PHYSICIAN

” Christ’s compassion toward the sick and his many healings of every kind of infirmity are a resplendent sign that “God has visited his people” and that the Kingdom of God is close at hand. Jesus has the power not only to heal, but also to forgive sins; he has come to heal the whole man, soul and body; he is the physician the sick have need of.  His compassion toward all who suffer goes so far that he identifies himself with them: “I was sick and you visited me.”  His preferential love for the sick has not ceased through the centuries to draw the very special attention of Christians toward all those who suffer in body and soul. It is the source of tireless efforts to comfort them.”
CCC 1503

“”Heal the sick!”  The Church has received this charge from the Lord and strives to carry it out by taking care of the sick as well as by accompanying them with her prayer of intercession. She believes in the life-giving presence of Christ, the physician of souls and bodies. This presence is particularly active through the sacraments, and in an altogether special way through the Eucharist, the bread that gives eternal life and that St. Paul suggests is connected with bodily health.
CCC 1509

– Adapted from the Catechism of Catholic Church, more details here.