Holy oil is the tangible matter used in the sacraments of Confirmation, Anointing of the Sick, and Holy Orders. While holy oil is used in baptism, it is not essential to the sacrament.
Like water, oil is an ancient symbol from the Mediterranean world. Olive oil was healthy to ingest and was used as a component in topical medications. Athletes and soldiers would anoint themselves with oil before they entered competition or combat. Borrowing these themes, holy oil is a means by which Christ strengthens Christians. Often the term “Soldier of Christ” would be applied to a person who received Confirmation. As a healing theme in the sacrament of the Anointing of the Sick, blessed oil is used as the matter of the sacrament. Jesus is the divine physician who comes to heal us both physically and spiritually in the anointing.
There are three kinds of blessed oil—catechumen, the sick, and Chrism. The oils are blessed at a special Mass during Holy Week, usually held on the morning of Holy Thursday, known as the Mass of Chrism. At this Mass, the priests of the diocese gather around their bishop and renew their priestly commitment. The bishop blesses these oils, which will later be divided among the parish for the sacramental life. Great symbolism of unity is expressed since the oil is blessed at the mother church of the diocese, the cathedral, with all the bishops’ representatives to the parishes (the priests), and then dispersed from this central place.
Oil of catechumens (oleum sanctorum in Latin) is used as a prebaptism anointing. In the case of baby baptisms, it is done right at the celebration of the sacrament. For adult converts, this anointing can take place months beforehand. This idea comes from the fourth century, when the church was receiving many converts and baptism could require several months or even many years of preparation. Oil, which has the spiritual meaning of strengthening, was used to strengthen the convert with Christ as he or she journeyed to the sacraments.
Oil of the Sick (oleum infirmorum) is used in the Sacrament of the Anointing. It is the outward sign that confers grace. After the priest imposes hands on the sick person, he then anoints the candidate’s forehead and hands with the oil. Inwardly, if the person is receptive, healing takes place. It may be only spiritual healing and strengthening of the infirm to deal with his maladies. At times, physical healing can also occur.
Chrism Oil (sacrum chrisma) is quite special and set apart from the other two. Chrism derives its name from the Greek word Christos from which we get Christ. “Christ” means “the Anointed One.” This oil is used in the sacraments of Confirmation and Holy Orders to confer the sacrament. It is also used in the sacrament of Baptism when confirmation will not immediately follow. Chrism is a mixture of balsam and olive oil. Balsam is an aromatic scent derived from special trees in the Mediterranean world, formerly reserved for royalty and priests. This is fitting in the sacramental sense, since Baptism makes us adopted children of God and we share in the priesthood of the laity.
All three oils are stored in a wall cupboard, known as an ambry. In light of the Second Vatican Council the ambry has taken on a significant role in church architecture. The ambry was once hidden in the sacristy or side chapel, but now it is placed in the sanctuary and made of glass with lights inside to show off the containers, which are also made glass.