הכרת תכרת
One of the less noticed subjects in פרשת שלח is the subject of blasphemy. The Torah tells us that one who curses G-d, will suffer a very serious punishment. The language of the text is very harsh as it says הכרת תכרת, that such a transgressor shall surely be cut off from the Jewish people. The Ramban notes that there are three types of כרת that are mentioned in the Torah. It’s written ונכרתה האיש, and that man shall be cut off. It’s also written, ונכרתה הנפש, and that soul shall be cut off. The most severe is הכרת תכרת. Some sins come from the weakness of controlling one’s lusts and result in ונכרתה האיש, that could be related to sexual transgressions. The ונכרתה הנפש, might be cases where one violates the prohibition of eating Chametz on Pesach, or not fasting on Yom Kippur. Repentance is a realistic possibility to atone for such sins. But directly cursing Hashem is the most serious offense of all. It is evident from the language of הכרת תכרת.