305 the work of His hands."409 Man, by possessing a soul of spiritual substance, partakes of the nature of angels, and by possessing a body partakes of the nature of the heavenly bodies. It is therefore, his privilege, as well as his duty, to offer to God the twofold homage of body and soul; in other words, to honor Him by internal and external worship. 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 [322] 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