Kal Va’Chomer

One of the ways that Jewish Law is established, is called, “Kal Vachomer.” This is referred to as a fortiori reasoning.

An example of such reasoning is found in a conversation between Moshe Rabbeinu and Hashem. Moshe argues with this method by saying, “If the Jewish people don’t believe in me, how will Pharoah believe me, when I am heavy of tongue.”

An example in Halacha of this principle is used in connection with Yom Tov. If something is forbidden on Yom Tov, a fortiori, or Kal Vachomer, it will be forbidden on Shabbat.

If the prohibition applies in a lesser situation, it will certainly apply in a more severe situation.

Another example from the Torah teaches that a Kohein may not marry a Jewish woman who has had relations with a non-Jew. Such a woman is forbidden to eat Teruma, the sanctified food reserved for Kohanim.

A Kohein’s daughter, if she is divorced and is childless, she may resume eating Teruma in her father’s house.

If a Bat Kohein divorcee, is not permitted to marry a Kohein, (as divorcees are forbidden) and yet she can eat Teruma, then Kal Vachomer the woman who is forbidden to eat Teruma, is forbidden to marry a Kohein.

There are numerous examples where we apply this reasoning. But we first saw its application with Moshe Rabbeinu’s conversation with Hashem.