2 This we have undertaken in our present discourse: may Christ help us, the Son of a virgin, and the Spouse of virgins, born after the flesh of a virgin womb, and wedded after the Spirit in virgin marriage. Whereas, therefore, the whole Church itself is a virgin espoused unto one Husband Christ, as the Apostle says, of how great honor are its members worthy, who guard this even in the flesh itself, which the whole Church guards in the faith? Which imitates the mother of her husband, and her Lord. For the Church also is both a mother and a virgin. For whose virgin purity consult we for, if she is not a virgin? Or whose children address we, if she is not a mother? Mary bare the Head of This Body after the flesh, the Church bears the members of that Body after the Spirit. In both virginity hinders not fruitfulness: in both fruitfulness takes not away virginity. Wherefore, whereas the whole Church is holy both in body and spirit, and yet the whole is not virgin in body but in spirit; how much more holy is it in these members, wherein it is virgin both in body and spirit?
Source: On Holy Virginity (New Advent)