DEUT137 Most people need inner wisdom. Perhaps the duties of the heart are so obvious and well known to all, I thought, and people are so faithful in fulfilling them, that it was unnecessary to write a book about them. But when I made an inquiry into the conduct of previous generations as documented in written records, I found that the people were far removed from them. Only the most fervent and outstanding personalities among the people lived up to these duties, as we know from accounts of their conduct; the rest of the people, however, sorely needed guidance and instruction in this area. How much the more so in our generation! Most of the people do not take seriously the duties of the limbs, certainly not the duties of the heart. Those among the people who are drawn to Torah study aim only to be considered scholars by the common people and to be thought of as great men. They veer off the path of the Torah to [study] that which brings no excellence of character, does not correct personal faults, and ignorance of which brings no punishment, while neglecting the study of the fundamentals of the religion and the foundations of the Torah, which should not be ignored or forsaken. Without knowledge of these [fundamentals and foundations] and without practicing them, one simply cannot fulfill the commandments. Belief in the unity of God is an example: Is this something which we are obligated to investigate intellectually, or is it enough to know of it by way of tradition and declare--as the simple do--without argument or proof, that our God is one? Must we investigate the meaning of “the absolute one” and “the relative one,” in order to differentiate between this meaning and that of the other existing unities? It is forbidden for a believer to remain in ignorance of these matters, for the Torah has cautioned us in this regard, saying: “Understand it today and reflect on it in your heart: Hashem is the God in the heavens above and on the earth below” (Devarim 4:39). The same is true of the other duties of the heart which have been mentioned and which will be mentioned: the believer's faith is not complete unless he knows of them and practices them. This is the inner wisdom, which is the light of the heart and the radiance of the soul. It is this that the verse refers to, saying: “Surely You desire truth in the inward parts; teach me wisdom in my innermost being” (Tehillim 51:8).