What is the main theme of judaism?
The main theme can be summed up in this statement by Rabbi Hillel: what is hateful to you, do not do to another. That is the whole Torah. The rest is commentary. Now go study.
All the hundreds of mitzvoth (commands), principles and beliefs of the Torah. Though it may have an associated culture and one or more associated languages, the traditional definition of Judaism is the observance of the Torah, which is why dictionaries define Judaism as "the religion of Moses." In this sense, the word "Torah" is meant in its wider meaning, which includes the Tanakh, the Talmud, and other classical Jewish texts. The philosophy of Judaism is…
Abraham is not the main prophet of Judaism. Abraham was not regarded as a prophet. Judaism, unlike Christianity and Islam, does not have a main prophet. Moses is often considered the greatest prophet because of his achievement and his closeness to God. All prophets after Moses are said to have only glimpsed what Moses saw.