99 Taking all these things, therefore, into consideration, I think that I am not rash in saying that there are some in the house of God after such a fashion as not to be themselves the very house of God, which is said to be built upon a rock, which is called the one dove, which is styled the beauteous bride without spot or wrinkle, and a garden enclosed, a fountain sealed, a well of living water, an orchard of pomegranates with pleasant fruits; which house also received the keys, and the power of binding and loosing. If any one shall neglect this house when it arrests and corrects him, the Lord says, "Let him be unto you as an heathen man and a publican." Of this house it is said, "Lord, I have loved the habitation of Your house, and the place where Your honor dwells;" and, "He makes men to be of one mind in an house;" and, "I was glad when they said unto me, Let us go into the house of the Lord;" and, "Blessed are they that dwell in Your house, O Lord; they will be still praising You;" with countless other passages to the same effect.
This house is also called wheat, bringing forth fruit with patience, some thirty-fold, some sixtyfold, and some an hundredfold. This house is also in vessels of gold and of silver, and in precious stones and imperishable woods. To this house it is said, "Forbearing one another in love, endeavoring to keep the unity of the Spirit in the bond of peace;" and, "For the temple of God is holy, which temple you are." For this house is composed of those that are good and faithful, and of the holy servants of God dispersed throughout the world, and bound together by the unity of the Spirit, whether they know each other personally or not.
But we hold that others are said to be in the house after such a sort, that they belong not to the substance of the house, nor to the society of fruitful and peaceful justice, but only as the chaff is said to be among the grain; for that they are in the house we cannot deny, when the apostle says, "But in a great house there are not only vessels of gold and of silver, but also of wood and of earth; and some to honor, and some to dishonor." Of this countless multitude are found to be not only the crowd which within the Church afflicts the hearts of the saints, who are so few in comparison with so vast a host, but also the heresies and schisms which exist in those who have burst the meshes of the net, and may now be said to be rather out of the house than in the house, of whom it is said, "They went out from us, but they were not of us." For they are more thoroughly separated, now that they are also divided from us in the body, than are those who live within the Church in a carnal and worldly fashion, and are separated from us in the spirit.
Source: On Baptism, Against the Donatists (New Advent)