This Sacrament is not to be given to all sick persons, but only to such as seem to be near to death from sickness. If they recover, this Sacrament may be administered to them again, if they are again reduced to the like state. For the unction of this Sacrament is not an unction of consecration, like the unction of Confirmation, the ablution of Baptism, and certain other unctions, which are never repeated, because the consecration always remains so long as the thing consecrated lasts: but the anointing in this Sacramentis for healing, and a healing medicine ought to be given again and again as often as the sickness recurs.
Though some are in a state near to death without sickness, as are persons condemned to death, and they would need the spiritual effects of this Sacrament, still this Sacrament is not to be given to them, but only to the sick, since it is given under the form of bodily medicine, and bodily medicine is not proper except for one bodily sick. For in the administration of Sacraments their signification must be observed.*
Oil is the special matter of this Sacrament, because it is of efficacy for bodily healing by mitigation of pains, as water, which washes bodies, is the matter of the Sacrament in which spiritual cleansing is performed. And as bodily healing must go to the root of the malady, so this unction is applied to those parts of the body from which the malady of sin proceeds, as are the organs of sense.
And because through this Sacrament sins are forgiven, and sin is not forgiven except through grace, clearly grace is conferred in this Sacrament. Nor is a bishop necessary to give this Sacrament, since the Sacrament does not bestow any excellence of state, as do those Sacraments in which a bishop is the minister.* Since however a great abundance of grace, proper to effect a perfect cure, is required in this Sacrament, it is right that many priests should take part in the rite,* and that the prayer of the whole Church should help out the effect of this Sacrament: hence James says: Let him bring in the priests of the Church, and the prayer of faith shall save the sick man. If however only one priest be present, he is understood to confer the Sacrament in the power of the whole Church, whose minister he is, and whose person he bears. As in other Sacraments, the effect of this Sacrament may be hindered by the insincerity (fictionem) of the recipient.
4.72 : Of the need of the Sacrament of Penance, and of the Parts thereof
4.74 : Of the Sacrament of Order