We have seen that the reason bids us recognize our duty to God in return for his goodness to us. At the same time we are not left to the suggestions and promptings of the reason alone. We have a positive law prescribing our conduct and the manner and measure of expressing our gratitude to God. This is made necessary by the constitution of man's nature. He is a composite of body and spirit. The former is at home in this lower world and is endowed with powers and qualities which tend to strengthen it at the expense of the spirit, a stranger in this world. Hence the necessity of a positive law to cure the spirit from the ills of the body by forbidding certain kinds of food, clothing, sexual indulgence, and so on, which strengthen the appetites, and commanding such actions as prayer, fasting, charity, benevolence, which have the opposite tendency of strengthening the reason. The positive law is necessary and useful besides because it prescribes the middle way, discouraging equally the extremes of asceticism and of self-indulgence. It regulates and defines conduct, and makes it uniform for old and young, intelligent and unintelligent. It institutes new occasions of worship and thanksgiving as history reveals new benefactions of God to his people in various generations. The law also contains matters which the reason alone would not dictate, and of which it does not understand the meaning. Such are the "traditional commandments." The reason why the law prescribes also some of the principles of the "rational commandments" is because at that time the people were so sunk in their animal desires that their minds were weakened, and there was need of putting both classes of commandments on the same level of positive prescription. But now the intelligent person observes them in accordance with their distinct origin, whereas the masses simply follow the law in both. The admonition of the positive law serves as an introduction to the suggestions of our own reason and prepares the way for the latter. The first is absolutely necessary for the young, the women and those of weak intellectual power. To worship God not merely because the law prescribes it, but because reason itself demands it denotes a spiritual advance, and puts one in the grade of prophets and pious men chosen of God. In this world their reward is the joy they feel in the sweetness of divine service; in the next world they attain to the spiritual light which we cannot declare or imagine.[123]