The term "chrism" is taken from the Greek chrisma which referred to a substance used for anointing. The title of Christ given to Jesus means “anointed one.”  In the early Church, the oil used for anointing during initiation came to be referred to as Chrism. As the Church grew in its early centuries, bishops found it necessary to depute to presbyters the authority to initiate and so they began to consecrate Chrism for use by presbyters in the initiation of new Christians. Today, Chrism is a sacred oil made from olive oil and perfumed with balsam and is consecrated only by the bishop. The use of the Sacred Chrism is an expression of the unity of the local Church around her bishop.  Sacred Chrism is used in baptism, confirmation, and the ordination of priests and bishops, as well as in the dedication of an altar and a church. The Chrism Mass takes its name from the Chrism which is consecrated during a special Mass traditionally celebrated on the morning of Holy Thursday. The Oil of Catechumens and the Oil of the Sick are also blessed during this Mass. The priests from throughout the diocese gather to receive the holy oils they will use throughout the year.

Traditionally this Mass is held on the morning of Holy Thursday. However, because of the distances traveled and the preparations needed for the Sacred Triduum, many dioceses, including the Diocese of Austin, celebrate this solemn Mass earlier in Holy Week to allow the priests and faithful to more easily participate in this Mass.

Holy Thursday commemorates the anniversary of Christ’s institution of the ministerial priesthood at the Last Supper. In modern times, following the homily, priests renew the promises they made at their ordination; promises to conform their lives more closely to Christ, to be faithful stewards of the Eucharist and other liturgical rites, and to be faithful teachers of the faith. The faithful are asked to pray for their priests and finally, all are asked to pray for the bishop that he may be a more perfect image of Christ, the Good Shepherd, Teacher, and Servant.