Anointing of the Sick is the sacrament that is received by those who are ill or suffering. By the sacred anointing and the prayer of the priest, the whole Church commends those who are sick to Christ. The sick person receives the Holy Spirit’s gifts of strength, faith, peace, and courage, and his or her suffering is united with the suffering of Christ for the building up of the Church (Catechism of the Catholic Church [CCC], nos. 1520-23).
Through the Sacrament of Anointing of the Sick, the Church carries out Jesus’ mission of compassion and healing for the sick. The one who is ill can also be a minister to others. By uniting their suffering to Christ, those who are sick can be signs of faith and witnesses of Christ’s Resurrection to the entire community (Pope John Paul II, Christifideles Laici [The Vocation and the Mission of the Lay Faithful in the Church and in the World ], no. 54).
The Rite of Anointing tells us there is no need to wait until a person is at the point of death to receive the Sacrament. A careful judgment about the serious nature of the illness is sufficient. The Sacrament may be repeated if the sick person recovers after the anointing but becomes ill once again, or if, during the same illness, the person's condition becomes more serious. A person should be anointed before surgery when a dangerous illness is the reason for the intervention (cf. Rite of Anointing, Introduction, nos. 8-10).
Moreover, "old people may be anointed if they are in weak condition even though no dangerous illness is present. Sick children may be anointed if they have sufficient use of reason to be comforted by this sacrament. . . . [The faithful] should be encouraged to ask for the anointing, and, as soon as the time for the anointing comes, to receive it with faith and devotion, not misusing the sacrament by putting it off" (Rite of Anointing, nos. 11, 12, 13).