This mitzvah prohibits blaspheming or cursing Hashem, the ultimate expression of disrespect toward the Divine. The Torah commands that speech, which is uniquely human and reflects the Divine image within man, must be guarded with reverence. To misuse speech against the Creator is not merely a verbal offense but a fundamental denial of Divine authority and presence. This prohibition preserves the sanctity of the Divine Name and trains the Jew to recognize that speech is a sacred instrument, meant for Torah, prayer, and blessing rather than degradation.

Rambam

• Sefer HaMitzvos, Lo Ta’aseh 60: Prohibits blaspheming the Divine Name.
• Hilchos Avodah Zarah 2:7; Sanhedrin 15:10: Blasphemy is one of the gravest offenses, punishable by stoning when performed with the explicit Divine Name.
• The severity reflects the centrality of reverence for Hashem.

Sefer HaChinuch

• Mitzvah 70: The root of the mitzvah is to implant awe and reverence for Hashem within the heart.
• Speech that dishonors the Creator erodes the moral and spiritual foundation of the soul.
• The mitzvah trains the tongue toward holiness and restraint.

Rashi

• On “אֱלֹהִים לֹא תְקַלֵּל” (Shemos 22:27):
  This refers to cursing Hashem.
• Rashi notes the Torah uses a term that can also refer to judges, teaching reverence for both Divine and earthly authority.

Ramban

• Blasphemy represents the ultimate rebellion against Divine sovereignty.
• It is not merely disrespect but a denial of the Creator’s authority over existence.

Talmud

• Sanhedrin 56a: Blasphemy is one of the Seven Noahide Laws, binding on all humanity.
• Sanhedrin 60a–61a: Details the laws and conditions under which blasphemy is punishable.
• Demonstrates the universal importance of honoring the Divine Name.

Midrash & Chazal

• Sifra, Emor: Blasphemy severs a person from the sanctity of the Divine.
• Vayikra Rabbah 32: Speech reflects the soul; corrupt speech corrupts the spirit.

Acharonim & Modern Torah Giants

• Rav Hirsch
  Speech is the highest expression of the Divine image in man; to use it against Hashem is a betrayal of that image.
• Chafetz Chaim
  The sanctity of speech must be preserved; misuse of the tongue distances the soul from holiness.
• Netziv
  Reverence for the Divine Name underlies all mitzvos.
• Rav Kook
  Speech directed toward Hashem should elevate the soul; blasphemy distorts the spiritual essence of man.

Chassidic & Mussar Classics

• Baal Shem Tov
  Every word has spiritual power; holy speech draws the Shechinah near.
• Tanya
  Speech expresses the inner soul; corrupt speech damages spiritual sensitivity.
• Sfas Emes
  Words are vessels for Divine light; misuse of speech blocks that light.
• Ramchal
  Guarding speech is essential to spiritual refinement and reverence.

Contrast with Mitzvah 210 — Not to Take Hashem’s Name in Vain

• Mitzvah 26: Prohibits cursing or blaspheming the Divine Name.
• Mitzvah 210: Prohibits using the Name frivolously or falsely.
• One is outright rebellion; the other is misuse or disrespect.

Parallel to Mitzvah 6 — To Sanctify Hashem’s Name

• Mitzvah 6: Positive command to honor and sanctify the Name.
• Mitzvah 26: Prohibition against degrading it.
• Together, they define the boundaries of holy speech.