Who Is a Jew?

Who is a Jew, According to the Torah?
Is being Jewish passed along by the father or the mother? Has that ever changed? What made our ancestors Jewish? Where in the Torah does it say what makes a person Jewish? Did the Rabbis change this Law?

Was King David Jewish?
Does Halachah (Jewish Law) consider King David a Jew, or has Jewish Law changed since then? What is the Torah’s definition of a Jew? Were Abraham and Sarah Jewish? Did Abraham know the Torah? Were there converts in Biblical times? Did Ruth convert? Did Moses marry a Gentile woman?

Judaism: Race, Religion, or Ethnicity?
Is being Jewish related to being part of a race or a religion? Is it cultural? No matter what position you take in this matter, this is probably not the answer you’re expecting.