The Diocese of Phoenix celebrated its annual Chrism Mass this week, consecrating three holy oils that will be used by the diocese over the next year.

"140 priests joined Bishop Olmsted and Bishop Nevares tonight at the annual Chrism Mass," the diocese posted on Facebook Tuesday. "Thank you Lord for the gift of the priesthood and all of our holy priests in the Diocese of Phoenix."

The Chrism Mass is one of the special Masses typically celebrated during Holy Week, a report from the U.S. Conference of Catholic Bishops said. 

Holy Week, which runs from Palm Sunday through Easter, is a time when Catholics commemorate Judas' betrayal of Jesus, the institution of the Eucharist, Jesus' Passion and Crucifixion, his burial and his Resurrection, a report from Britannica said. 

During the Chrism Mass, the priest consecrates three oils: the Oil of the Sick, the Oil of the Catechumens, and the Chrism. 

Each oil has a special purpose in the Church. A report on SimplyCatholic.com explains each of them.

The Oil of the Sick is used in the Sacrament of the Anointing of the Sick. During this sacrament, a priest lays hands on a sick or elderly person, prays for them, and anoints their head and hands with oil. 

The Oil of the Catechumens is used to anoint children and adults before baptism. 

Chrism oil is used for a person's consecration to God, such as during the Sacrament of Confirmation.