There are two parts to the Torah:
1. Written Torah
2. Oral Torah
The Torah was given to Moses in written form (Ten Commandments) with oral commentary. The Torah is the primary document of Judaism. Torah, which means "law". God revealed the Torah through Moses. It is thus written, "Moses commanded us the Torah, an inheritance to the congregation of Jacob" (Deut. 33:4). God's revealed instructions to the Jewish People. It teaches Jews how to act, think and even feel about life and death. It also teaches how man should worship God or treat his neighbor.
The entire Torah was given to Moses during two intervals. The first part was given during the year after the Exodus. The rest was given shortly before Israel crossed the Jordan at the end of the 40 years in the desert. Moses then wrote down this Torah. He gave it to Levi's descendants, the priests in charge of the Ark of G-d's covenant, and another 12 copies to the elders (of the tribes) of Israel.
Because the Torah reveals God's will to man, it was given letter by letter to avoid any misinterpretation. Throughout all generations, great care was taken to preserve the Torah exactly as it was given by Moses. The scribe is thus given the advice, "Be careful with your task, for it is sacred work -- if you add or subtract a single letter, you will destroy everything."
Since every Torah must be letter perfect, it must be carefully copied from another scroll. It is forbidden to write a single letter without copying it from another Torah. Originally, the Torah and other scripture were so carefully preserved that every letter, word, and sentence was counted. Traditions still exist based on this knowledge.
The Torah contains 613 commandments (mitzvot). The Ten Commandments are considered the most important commandments of the Torah. The Torah also contains stories that teach us about God's relationship with the Jewish People.
The Written Torah is often called the Tanakh, which stands for Torah (T), Nevi'im (N) and Ketuvim (K). The Written Torah contains:
1. Five Books of Moses (Torah - Chumash)
2. Prophets (Nevi'im)
3. Writings (Ketuvim)
The Five Books of Moses (also called Chumash from the Hebrew word for five). Were given to the Jewish People at Mount Sinai during their exodus from Egypt approximately 3500 years ago. They include Genesis (Beresheet), Exodus (Shemot), Vayikra (Leviticus), Numbers (Bamidbar), and Deuteronomy (Devarim).
Are direct prophecies or recordings of what God said to the prophets. Writings (Ketuvim) are books written by the prophets with the guidance of God.
The Ketuvim, or Hebrew literary books, are subdivided into three major parts: Wisdom Literature, Megillot (scrolls), and Histories
Because the books included in Tanakh were mainly written in Hebrew, the Tanakh is sometimes referred to as the Hebrew Bible. Christians refer to the Tanakh as the Old Testament to differentiate it from later writings they also consider holy.
The Oral Torah, explanations of the Written Torah, was originally passed down verbally from generation to generation.
After the destruction of the Temple in Jerusalem, it was decided the Oral Torah should be written down so it would not be forgotten. In the 2nd century C.E., Rabbi Yehuda HaNasi and a group of Sages compiled the Mishnah. The Mishnah is a written outline of the Oral Torah.
Over the next few centuries, Jewish scholars studied the Mishnah. Their discussions, questions and decisions became known as the Gemara. The Gemara is commentaries elaborating on the Mishnah.
The Talmud is the combination of the Mishnah and Gemara together. In the 4th century, the Jerusalem Talmud was compiled in Israel. In the 5th century, the Babylonian Talmud was compiled in Babylon. The Babylonian Talmud is studied and used more than the Jerusalem Talmud because it is more comprehensive.