Yeshayahu Leibowitz was an Orthodox Jew who held controversial views on the subject of halakha, or Jewish law. He wrote that the sole purpose of religious commandments was to obey God, and not to receive any kind of reward in this world or the world to come. He maintained that the reasons for religious commandments were beyond man's understanding, as well as irrelevant, and any attempt to attribute emotional significance to the performance of mitzvot was misguided and akin to idolatry. The essence of Leibowitz's religious outlook is that a person's faith is his commitment to obey God, meaning God's commandments, and this has nothing to do with a person's image of God. This must be so because Leibowitz thought that God cannot be described, that God's understanding is not man's understanding, and thus all the questions asked of God are out of place. One result of this approach is that faith, which is a personal commitment to obey God, cannot be challenged by the usual philosophical problem of evil or by historical events that seemingly contradict a divine presence. If a person stops believing after an awful event, it shows that he only obeyed God because he thought he understood God's plan, or because he expected to see a reward. But “for Leibowitz, religious belief is not an explanation of life, nature or history, or a promise of a future in this world or another, but a demand.”