The laws may also be classified as 1. Commandments of the heart, 2. Commandments of the tongue, and 3. Commandments of action. An example of commandments of the heart is, "Thou shalt love the Lord thy God," "Thou shalt not hate thy brother in thy heart," and so on. To the commandments of the tongue belong the reading of the _Shema_, grace after meals, the priestly benediction, and so on. The laws of the third class are so numerous that there is no need of mentioning them. The laws of the heart are the most important of all. The reader will recognize in this two-fold classification Saadia's division of the laws into rational and traditional, and Bahya's classification of duties of the heart and duties of the limbs. This second class includes Ibn Ezra's second and third classes, tongue and action.[219] The problem of evil Ibn Ezra solves by saying that from God comes good only. The world as a whole is good; evil is due to the defect of the object receiving higher influence. To argue that because of the small part of evil the whole world, which is good, should not have been created, is foolish. The highest good of man is to develop his reason. As the traveller and the captive long to return to the land of their birth and be with their family, so the rational soul is eager to rise to the upper world which is not made of clay. This it can do only if it purifies itself from the uncleanness of corporeal desire which drags it down, and takes pains to know its own nature and origin, with the help of Wisdom whose eyes are undimmed. Then she will know the truth, which will remain indelibly impressed upon her when she separates from the body, where she was put for her own good. The suffering she underwent here for a time will give place to everlasting rest and joy. All man's work is vain, for man can neither create nor annihilate a substance. All his corporeal activity consists in combination and separation of accidents. The only thing of value is the fear of God. But no man can rise to this stage until he has ascended the ladder of wisdom, and has acquired understanding.[220] More concretely the way to purify the soul from the body is by uniting the rational and spirited soul, as Plato has it, against the appetitive, and giving the reason the mastery over the spirited soul as well. A moderate degree of asceticism is to be recommended as favoring the emancipation of the soul from the tyranny of the body. This is the meaning of the institution of the Nazirite; and the offering he must bring after the expiration of his period is to atone for the sin of returning to a life of indulgence. But one should not go to extremes. Too much praying and fasting results in stupefaction. It is a mistake to develop one side of one's nature at the expense of another. Every one of the three souls (the rational, the spirited and the appetitive) must be given its due.