The first unit of the Hebrew Bible is the Torah, which comprises the five books of Moses. According to Jewish belief, Moses received the Torah from God on Mount Sinai, along with its verbal explanations and commands (Talmud). Each week a larger chapter from the Torah is read publicly, which called the weekly portion. The Torah scribe, called the Sofer, writes the Torah on a parchment prepared according to strict rules, and with ink proper of ritual requirements. One must follow the specifications laid down in the tradition when writing and using the Torah, otherwise the Torah is “pasul”, the opposite of kosher.