In instituting the sacraments Christ did not determine the matter and form down to the slightest detail, leaving this task to the Church, which should determine what rites were suitable in the administration of the sacraments.These rites are indicated by the word Sacramentalia, the object of which is to manifest the respect due to the sacrament and to secure the sanctification of the faithful.
They belong to widely different categories, e.g.: substance, in the mingling of water with Eucharistic wine; quantity, in the triple baptismal effusion; quality, in the condition of unleavened bread; relation, in the capacity of the minister; time and place, in feast-days and churches; habit, in the liturgical vestments; posture, in genuflection, prostrations; action, in chanting etc.
So many external conditions connect the sacramentals with the virtue of religion, their object being indicated by the Council of Trent (Sess. XXII, 15), that it is asserted that apart from their ancient origin and traditional maintenance ceremonies, blessings, lights, incense, etc. enhance the dignity of the Holy Sacrifice and arouse the piety of the faithful. Moreover the sacramentals help to distinguish the members of the Church from heretics, who have done away with the sacramentals.