Deacons can baptize and they can witness marriages, they can even distribute communion as an ordinary minister, and yet the Church does not allow deacons (nor any who are not priests) to confer the sacrament of Anointing of the Sick.
A brief consideration of this question – Why can’t a deacon confer Anointing of the Sick? – will teach us a great deal about this sacrament.
None but the priests can confer Anointing of the Sick
That only priests (including bishops) can confer the sacrament of Anointing is the clear teaching of the Catholic Church.
“Only priests (bishops and presbyters) are ministers of the Anointing of the Sick.” (CCC 1516)
“Every priest, but only a priest, can validly administer the anointing of the sick.” (Code of Canon Law 1003.1)
“All priests, and only priests, validly administer the anointing of the sick.” (Eastern Code of Canon Law 739.1)
“Further, it is also indicated there [James 5:14] that the proper ministers of this sacrament are the presbyters of the Church, under which name in that place are to be understood not the elders by age or the foremost in rank among the people, but either bishops or priests duly ordained by them with the imposition of the hands of the priesthood [1 Timothy 4:14].” (Trent, Session XIV)
That priests and only priests can confer this sacrament is clearly taught in Sacred Scripture: Is any man sick among you? Let him bring in the priests of the church, and let them pray over him, anointing him with oil in the name of the Lord. (James 5:14)
This is not the type of teaching which can change. The minister of the sacrament of Anointing of the Sick has been and will always be priests and only priests (including, of course, bishops). Still, we ask, Why is it so?
Anointing of the Sick forgives sin, even mortal sin
Anointing of the Sick is principally directed to spiritual healing. But what is the spiritual healing which this sacrament effects? St. James tells us that it forgives sin, and the Council of Trent teaches dogmatically that both mortal and venial sins are forgiven through this sacrament. However, the forgiveness of sin per se is not the principal effect of this sacrament, but is more of a side-effect. This is why St. James does not say simply, “Anoint the sick person and his sins will be forgiven”, but, if he be in sins, they shall be forgiven him. (5:15)
The sacrament given for the forgiveness of actual sins is Reconciliation or Confession. For the forgiveness of mortal and venial sin, Penance is the proper sacrament. This is why the Church encourages the faithful to receive the sacrament of Reconciliation in preparation for Anointing. Further, if a man were to attempt to receive Anointing of the Sick as a way of having his sins forgiven while despising and refusing Confession, the Anointing would have no effect in him except his condemnation. Again: Even though Anointing does forgive sin (and even mortal sin, but not original sin), if a man attempts to use this sacrament as a way of avoiding Confession, he condemns himself, and the Anointing becomes for him a marking unto judgment rather than a balm of forgiveness.
Anointing of the Sick is for the remission of sins, that is, of the remnants of sin
Still, Anointing of the Sick is for spiritual healing and is directed to the forgiveness of sins – however, it is not principally for the forgiveness of sin as to the guilt of sin (this is what Confession is for), but rather as to the “remnants” or “vestiges” of sin.
Actual sin weakens the will and burdens the soul. When a person begins to be in danger of death, he has need of a spiritual healing and strengthening so that he might be well prepared to meet his Lord in the particular judgment. Most especially, the sacrament of Anointing gives a special grace to strengthen the sick person “against the temptations of the evil one, the temptation to discouragement and anguish in the face of death.” (CCC 1520)
As the sacrament of Anointing removes all the “remnants” of sin (that perduring weakness of the will which remains even after sin has been forgiven), so too does it wash away any sin which it finds still staining the soul.
Additionally, if it is conducive to the spiritual healing of the individual, the sacrament may effect a physical healing as well.
Why only priests can anoint: Confession and Anointing
Now, seeing that Anointing is directed to the forgiveness of sins (that is, of the remnants of sin) and is truly a completion of the sacrament of Penance, it is becomes clear that only priests can confer this sacrament.
While it is true that deacons can baptize, we do not say that they can forgive sins. Indeed, the sacrament of baptism does forgive all sin (both original and actual sin), but it is not so much through the power of the minister as through the sanctifying power of regeneration through water and the Holy Spirit. Thus, we do not say that a priest or deacon or lay person “forgave that baby’s sins” when he baptized him – Baptism is not given through the “power of the keys”.
Hence, since Anointing is the completion of the sacrament of Penance (especially as to the effect of the two sacraments), and because Anointing is directed principally to spiritual healing through the remission of the remnants of sin, only those who have the power to absolve from sin through the sacrament of Reconciliation are able to confer Anointing of the Sick.
Since the “power of the keys” was entrusted only to the priests (and bishops), only these can confer Penance and Anointing. Because neither deacons nor the laity can hear confessions, neither can they confer Anointing of the Sick.
On the profound confusion regarding this sacrament in the Church today
1) Danger of death: First, there are many in the Church who do not realize that Anointing of the Sick can only be given to those who have begun to be in a real danger of death [for more on this, see our earlier article - here]. Surely, Anointing is not only for those who are on their death bed, but neither is it for those who do not suffer from a serious illness or from old age such that they have at least begun to be in danger of death. If Anointing is divorced from the notion of a spiritual healing in preparation for death and the particular judgment, then it will very likely be thought of as being principally for physical, emotional, and psychological healing.
I am convinced that this error – separating Anointing from danger of death – is the font of all the modern confusion about this sacrament. [n.b. Though many priests and even bishops are confused on this point, the Church still teaches that Anointing is only to be given to those who have begun to be in danger of death from sickness or old age (cf. CCC 1514, Code of Canon Law 1004.1, Eastern Code of Canon Law 738)]
2) Not principally about physical healing: Many in the Church today divorce Anointing of the Sick from Penance and speak as though this sacrament is not directed principally to the remission of the remnants of sin in preparation for a holy death. Such persons make the sacrament to be more about physical healing (including psychological comfort) than about spiritual healing (which is the forgiveness of sin and of the remnants of sin). Thus, it is no surprise that so many people in the Church do not understand why this sacrament can only be conferred by priests and bishops. Because they do not realize the close connection between Confession and Anointing, they do not realize that Anointing is sacramentally unintelligible if not seen as the completion of the sacrament of Penance.
3) Why young children cannot receive Anointing: From this second error, a third follows – people begin to think that the Church could (or, even, should) confer Anointing on young children below the age of reason. But, in truth, these youngsters have no need of the sacrament since they have not committed any sins. If Anointing were primarily about physical healing, then the Church would give the sacrament to young children (and there would be no clear reason why the sacrament couldn’t be given by deacons or even the laity). However, Anointing is primarily about spiritual healing gained through the remission of the remnants of actual sin. And, since young children below the age of reason have not yet committed any actual sins, they cannot receive Anointing of the Sick (they have no need of it, just as they have no need of Reconciliation). [for more on this, see our earlier article - here]