How does Catholic Church explain the use of singular word “name” in the Prayer of Sign of the Cross?
As Catholics, we call it a prayer, but in reality it is more a form of addressing the three Divine Persons of the Trinity.
The words in the phrase “in the name of the Father and of the Son and of the Holy Spirit” is more a statement of address on behalf of the Most Holy Trinity: Father,Son and Holy Spirit than an actual prayer.
In the name of is a phrase that simply means:
1.) representing someone or something
2.) using the authority given by someone or something
The above phrase is more a statement in who’s name the following prayer of action (baptism) is being done. There is in essence no prayer of adoration, contrition, petition or thanksgiving involved in this theological statement. Catholics and other denominations employ it out of love for the Most Holy Trinity as well by they very fact Our Lord asked us to baptize using this Tridentine formula.
Catholics say many of the same prayers other religions do, with some variations. The key Catholic prayers are either part of the Mass, during which many prayers are sung, or part of praying the rosary.
Traditionally, Catholic prayers fall into four types:
- Adoration: Praising God
- Contrition: Asking for God’s forgiveness
- Petition: Asking God for a favor
- Thanksgiving: Showing God gratitude
A Look at Key Catholic Prayers
Making the Sign of the Cross is not only traditional; it is also a sacramental.
Most commonly and properly the words "sign of the cross" are used of the large cross traced from forehead to breast and from shoulder to shoulder, such as Catholics are taught to make upon themselves when they begin their prayers, and such also as the priest makes at the foot of the altar when he commences Mass with the words: "In nomine Patris et Filii et Spiritus Sancti". (At the beginning of Mass the celebrant makes the sign of the cross by placing his left hand extended under his breast; then raising his right to his forehead, which he touches with the extremities of his fingers, he says: In nomine Patris; then, touching his breast with the same hand, he says: et Filii; touching his left and right shoulders, he says; et Spiritus Sancti; and as he joins his hands again adds: Amen.) The same sign recurs frequently during Mass, e.g. at the words "Adjutorium nostrum in nomine Domini", at the "Indulgentiam" after the Confiteor, etc., as also in the Divine Office, for example at the invocation "Deus in adjutorium nostrum intende", at the beginning of the "Magnificat", the "Benedictus", the "Nunc Dimittis", and on many other occasions. - Sign of the Cross (Catholic Encyclopedia)