Greek: leitos, public; ergon, work
A public service or duty. Among the ancient Greeks it designated the duty of an individual to provide, at his own expense, for public games held on religious festivals, to outfit ships for the benefit of the state, etc. In Scripture it is applied to the religious duty to be performed by priests and Levites in the Temple, especially in connection with the Sacrifice. In Christian use it has two senses: in the Eastern Churches it has almost always designated the Eucharistic Sacrifice alone; in the Western Church it designates either the Mass alone, with its accompanying prayers and ceremonies, or the whole collection of official services used in public worship. In this last sense it is equivalent to rite and may be defined as the exercise of public worship according to Church regulation. It comprises then, all those prayers, ceremonies, and functions prescribed by the Church for use in all services performed by an official minister in her name. It includes the celebration of Mass, the administration of the Sacraments (and Sacramentals), the recitation of the Divine Office, and all other functions such as processions and benedictions. It excludes devotions of a private nature such as the recitation of the Rosary.
The origin of Liturgy is to be found in the institution by Christ of the Holy Sacrifice of the Mass, and the Sacraments, as well as in His example and precepts concerning the necessity and mode of prayer. While Christ laid down the essentials, He left the development of details to His Church, who carries out this task under the guidance of the Holy Ghost. The Liturgy has not been the same at all times in the past, nor is it the same everywhere today. Four distinct types are discernible, Antiochene, Alexandrine, Gallican, and Roman, each branching into various derived liturgies, illustrating the ability of the Church, the jealous guardian of the essential elements, to accommodate her public worship, in nonessentials, to circumstances of time, place, and peoples.
The prayer of the Liturgy is admirably adapted to express the fundamental relations that exist between Creator and creature, considering the latter both as an individual and a member of society. Liturgy gives expression in an approved way to the adoration due to God as the Creator and Lord of all, to the thanksgiving due Him for the benefits received. In a more perfect way than is ordinarily possible in private prayers it sends up to God the cry of the human heart for grace and favor, and renders to Him propitiation for sin. In it the interior dispositions of the soul of the Church are beautifully and efficaciously manifested in forms at once approved for their purity of faith and dignified by antiquity. Every act of the Liturgy has its symbolical meaning; there is the spirit of adoration and humility in the genuflections and bows, the spirit of supplication and exultation in the elevation of hands, the spirit of Christian unity in the salutations of the priest to the people, as in Orate Fratres. The vestments used mark out the wearer as the representative of the great High Priest, Christ; their fine texture indicates the solemnity of the occasion, the various colors, white, red, green, violet, and black, signify purity and joy, charity, hope, penance, and mourning respectively. Nothing is vain in the Liturgy, every prayer, action, cere. mony, utensil, and vestment is expressive of some interior virtue possessed by the Mystical Body of Christ, to be striven for by the individual members.