The Catholic Church professes and teaches that the Sacred Anointing of the Sick is one of the seven Sacraments of the New Testament, that it was instituted by Christ and that it is "alluded to in Mark (Mk. 6:13) and recommended and promulgated to the faithful by James the apostle and brother of the Lord. If any one of you is ill, he says, he should send for the elders of the church, and they must anoint him with oil in the name of the Lord and pray over him. The prayer of faith will save the sick man and the Lord will raise him up again, and if he has committed any sins, he will be forgiven (James 5:14-15)."
From ancient times testimonies of the Anointing of the Sick are found in the Church's Tradition, particularly her liturgical Tradition, both in the East and in the West. Especially worthy of note in this regard are the Letter which Innocent I, our predecessor, addressed to Decentius, Bishop of Gubbio, and the venerable prayer used for blessing the Oil of the Sick: "Send forth O Lord, your Holy Spirit the Paraclete," which was inserted in the Eucharistic Prayer and is still preserved in the Roman Pontifical.
In the course of the centuries, in the liturgical Tradition the parts of the body of the sick person to be anointed with Holy Oil were more explicitly defined, in different ways, and there were added various formulas to accompany the anointings with prayer, which are contained in the liturgical books of various Churches. During the Middle Ages, in the Roman Church there prevailed the custom of anointing the sick on the five senses, using the formula: "Per istam Sanctam unctionem et suam piissimam misericordiam, indulgeat tibi Dominus quidquid deliquisti," adapted to each sense.
In addition, the doctrine concerning Sacred Anointing is expounded in the documents of the Ecumenical Councils, namely the Council of Florence and in particular the Council of Trent and the Second Vatican Council.
After the Council of Florence had described the essential elements of the Anointing of the Sick, the Council of Trent declared its divine institution and explained what is given in the Epistle of Saint James concerning the Sacred Anointing, especially with regard to the reality and effects of the sacrament: "This reality is in fact the grace of the Holy Spirit, whose anointing takes away sins, if any still remain to be taken away, and the remnants of sin; it also relieves and strengthens the soul of the sick person, arousing in him a great confidence in the divine mercy, whereby being thus sustained he more easily bears the trials and labors of his sickness, more easily resists the temptations of the devil 'lying in wait' (Gen. 3:15), and sometimes regains bodily health, if this is expedient for the health of the soul." The same Council also declared that in these words of the Apostle it is stated with sufficient clarity that "this anointing is to be administered to the sick, especially those who are in such a condition as to appear to have reached the end of their life, whence it is also called the sacrament of the dying.