Our English word “church” (A.S. cyrice, cirice; Germ. kirche) is derived from the Greek κυριακός, “belonging to the Lord” (1 Cor. 11:18, 22). It is used to denote: (1) a building set apart for God’s service, and also the service itself; (2) the faithful themselves, “Ye are God’s building” (1 Cor. 3:9); “Ye are the temple of the living God” (2 Cor. 6:16); (3) the clergy as distinguished from the laity (Matt. 18:17). The corresponding word in the New Testament, ἐκκλησία (ecclesia), in its orignal profane use, means “an assembly of the citizens summoned (ἐκκαλέω) by the crier;” and hence it was suited to designate the assembly of the faithful called by God’s grace and His ministers (“To the Church [τῇ ἐκκλησίᾳ] that is at Corinth … to them that are called to be saints (κλητοῖς ἁγίοις),” (1 Cor. 1:2). Except, perhaps, in one or two instances, the word συναγωγή (synagoga, “a bringing or driving together,” (συνάγω) is never used for Christ’s Church. “There is a difference,” says St. Augustine, “between synagoga and ecclesia: the former means a gathering together, the latter a calling together; even beasts are said to be gathered together, whereas calling together is properly applied to reasonable beings” (In Ps. lxxxi.; see also Catechism of the Council of Trent, Part I. ch. x. n. 3).

A complete definition of the Church is not possible at this stage of our inquiry. The various elements which go to form it will be gathered as we proceed. At present it will be sufficient to say that by the Church we mean the society or union of all who cleave to God by true supernatural worship.