Genuine piety cannot long be concealed in the heart without manifesting itself by exterior practices of religion; hence, though interior and exterior worship are distinct, they cannot be separated in the present life. Fire cannot burn without sending forth flame and heat. Neither can the fire of devotion burn in the soul without being reflected on the countenance and even in speech. It is natural for man to express his sentiments by signs and ceremonies, for "from the fulness of the heart the mouth speaketh;" and as fuel is necessary to keep fire alive, even so the flame of piety is nourished by the outward forms of religion.
A devoted child will not be content with loving his father in his heart, but will manifest that love by affectionate language, and by the service of his body, if necessary. So will the child of God show his affection for his heavenly Father not only by interior devotion, but also by the homage of his body. "I beseech you," says the Apostle, "by the mercy of God, that you present your bodies, a living sacrifice, holy pleasing unto God, your reasonable service."(410)
The fruit of a tree does not consist in its bark, its leaves and its branches. Nevertheless, you never saw a tree bearing fruit unless when clothed with bark, adorned with branches and covered with leaves. These are necessary for the protection of the fruit. In like manner, though the fruit of piety does not consist in exterior forms, it must, however, be fostered by some outward observances or it will soon decay. There is as close a relation between devotion and ceremonial as exists between the bark and the fruit of a tree.
The man who daily bends his knee to the Maker, who recites or sings His praises, who devoutly makes the sign of the cross, who assists without constraint at the public services of the Church, who observes an exterior decorum in the house of God, who gives to the needy according to his means and duly attends to the other practices and ceremonies of religion, will generally be one whose heart is united to God, and who yields to Him a ready obedience. Show me, on the contrary, a man who habitually neglects these outward observances of religion and charity, and I will show you one in whose soul the fire of devotion, if not quite extinguished, at least burns very faintly.