WLC Q.62: What is the visible church?
The visible church is a society made up of all such as in all ages and places of the world do profess the true religion, (1 Cor. 1:2, 1 Cor. 12:13, Rom. 15:9–12, Rev. 7:9, Ps. 2:8, Ps. 22:27–31, Ps. 45:17, Matt. 28:19–20, Isa. 59:21) and of their children. (1 Cor. 7:14, Acts 2:39, Rom. 11:16, Gen. 17:7)
WCF 25.2.
The visible Church, which is also catholic or universal under the Gospel (not confined to one nation, as before under the law), consists of all those throughout the world that profess the true religion; (1 Cor. 1:2, 1 Cor. 12:12–13, Ps. 2:8, Rev. 7:9, Rom. 15:9–12) and of their children: (1 Cor. 7:14, Acts 2:39, Ezek. 16:20–21, Rom. 11:16, Gen. 3:15, Gen. 17:7) and is the kingdom of the Lord Jesus Christ, (Matt. 13:47, Isa. 9:7) the house and family of God, (Eph. 2:19, Eph. 3:15) out of which there is no ordinary possibility of salvation. (Acts 2:47)