Holiness is the second property that the Nicene-Constantinopolitan Symbol attributes to the Church and which emanates from the intimate nature of the same. In fact, if the Church is "the union of Christ with man in a social form" it must be holy, like everything that is in contact with God. The Bible presents holiness as the characteristic attribute of the Church: «Christ loved the Church and gave himself for her, in order to sanctify it (…), to prepare her as an immaculate bride, without wrinkles and without moles" (Ephesus. 5, 26); «Christ chose us so that we might be holy and immaculate before him» (Ephesus. 1, 4): "He gave himself for us in order to redeem us from all iniquity and to purify himself into an acceptable and zealous people for good works" (Tit. 2, 14). The holiness of the Church is threefold: sanctity of principles, of the limbs, of charismas. The sanctity of principles consists in the fact that the Church is endowed with means that are suitable for producing sanctity in men (active sanctity). Really the dogmatic and moral doctrine of the Church (Magisterium) it is the ferment that lifts the human mass from the darkness of the earth to the splendors of the sky; his Sacraments (Ministry) they are the channels that transmit sanctifying grace; his authority (Empire) it tends only to guide the faithful along the path of perfection. The sanctity of the limbs results from the spectacle that has constantly occurred in the history of Christianity of many faithful living according to the precepts of the Gospel (common holiness) and many others who, also following the evangelical advice, they have reached the arduous heights of heroism (eminent sanctity), which is usually sanctioned by canonization. All the centuries of the history of Christian peoples, from San Paolo to San Benedetto, from Saint Francis of Assisi to Saint Teresa of Jesus, from San Vincenzo de' Paoli to San Giovanni Bosco are intersected by the luminous trail of heroic sanctity (passive sanctity). The sanctity of charisms emerges from the gift of miracles, with which the Holy Spirit usually manifests his presence throughout the mystical Body (they are in fact the miracles thanks gratis datae for the building of the Church) as in some member endowed with singular virtue, because God, ordinarily he uses the souls dearest to him to work his wonders (signs of holiness).
dal Dictionary of dogmatic theology, Piolanti, Relative, Garofalo – peace to their souls! – Studies, Roma, 1952.