What is this sacrament
Anointing of the Sick is one of the seven sacraments, and it is often one of the last, if not the last, sacrament that a person receives before death. It consists of anointing a person with the oil of the sick and praying for them. This anointing has the effects of preparing the person for death, forgiving sins, uniting that person's suffering with Christ's suffering and even in some circumstances the restoration of physical health.
In Scripture
It is a sacrament that is attested to in scripture. There are passages in the gospels speaking of Jesus and the apostles healing through anointing. The most explicit passage comes from the epistle of St. James. “Are any among you sick? They should call for the elders of the church and have them pray over them, anointing them with oil in the name of the Lord.” - James 5:14 This is an exact description of this sacrament.
Administering the Sacrament and its Effects
Previously, this sacrament was known as extreme unction and was only administered when someone was very close to death. Today, it is administered whenever anyone is seriously ill and could possibly die. This includes before major surgery, or if someone goes into the hospital with a serious illness. This is a sacrament which can be received multiple times. It can only be administered by a priest or a bishop.
There have been occasions where people have been known to receive physical healing after receiving the sacrament. This is an added benefit on top of spiritual health and not something to be expected. The primary end of this sacrament is to give graces to a person as they prepare to die. Death is not something to be feared, but it is also a time of great temptation, as the devil seeks to sway a person to evil before their earthly life ends. This sacrament will give additional spiritual strength to overcome these powerful temptations.
Potential Misunderstandings
One of the spiritual effects of this sacrament is the forgiveness of sins. This forgiveness of sins that is extended through this sacrament should not be in place of a sacramental confession. If it is possible for the person to go to confession, they should. It is primarily through the sacrament of penance that God forgives sins. The forgiveness of sins associated with this sacrament of the sick is for those who maybe don't have the opportunity to partake of the sacrament of penance. Perhaps they are so sick they can't communicate in any way. Through this sacrament, God will still forgive their sins if they are sincerely sorry for them.
It is important not to abuse this sacrament. There can be a tendency to want to receive it for every little illness or remote chance of death. It is very clearly only to be given when there is a serious chance for death, like before serious surgery or entering a battle. However, a person should also not wait to receive the sacrament until they are all but dead. It imparts many powerful graces to combat temptation and strengthen the soul, and if a person is in some sort of serious danger to their life, they should not hesitate to ask for and receive this sacrament. The sacrament loses much of its use if it is not received until a few moments before death when there was an opportunity to partake of it earlier. It is a gift of strength, and should be used whenever necessary.