What Does Each Tradition Forbid Saying About God?

Jewish law identifies several distinct categories of forbidden speech about God, and the rabbinic tradition spent centuries sharpening the distinctions between them.

The most fundamental prohibition is blasphemy — cursing God directly. The Torah states plainly: "You shall not revile God, nor put a curse upon a chieftain among your people" Exodus 22:27. The Talmud in tractate Sanhedrin unpacks this verse at length, debating exactly what verbal form constitutes a punishable offense. The Gemara notes that the Hebrew root tekallel (blaspheme) was chosen deliberately over a milder word, signaling that even demeaning speech about God — not just outright cursing — falls under the prohibition Sanhedrin 66a:27.

A second, equally serious category involves invoking the names of foreign gods. The Torah commands: "Make no mention of the names of other gods; they shall not be heard on your lips" Exodus 23:13. Maimonides (12th c.) and later Nachmanides debated whether this bans merely speaking pagan divine names in a worshipful context or any utterance whatsoever — a disagreement that remains live in halakhic literature.

The Talmud further develops the concept of chillul Hashem (desecration of the Name), which extends beyond direct blasphemy to any speech or action that brings God's reputation into disrepute. Tractate Sanhedrin 56a establishes that liability for blasphemy requires invoking the divine name itself Sanhedrin 56a:11, which is why rabbinic courts historically used a euphemism (yose yose) during blasphemy trials to avoid repeating the offense in court.

In practice, traditional Jews avoid writing or pronouncing the Tetragrammaton (YHWH) outside of prayer, substituting Adonai in liturgy and Hashem ("the Name") in everyday speech — a living expression of these prohibitions.

Christianity inherits the Hebrew Bible's prohibitions wholesale and builds upon them through the lens of the New Testament and subsequent theological tradition.

The Third Commandment — "You shall not take the name of the LORD your God in vain" — is the cornerstone. Early church fathers like John Chrysostom (4th c.) interpreted this as covering not just profane oaths but any flippant, dishonest, or manipulative invocation of God's name. The Catechism of the Catholic Church (§2148) extends the prohibition to blasphemy, perjury, and false prophecy spoken in God's name.

The prohibition on naming other gods carries over directly from the Hebrew scriptures: "Make no mention of the names of other gods; they shall not be heard on your lips" Exodus 23:13. Patristic writers applied this to Greco-Roman deities and, later, to any speech that treated rival spiritual powers as coordinate with the God of Israel.

A distinctively Christian concern is the sin against the Holy Spirit — what Jesus calls the one unforgivable blasphemy (Matthew 12:31-32). Theologians from Augustine to Karl Barth (20th c.) have debated what exactly this means, but the consensus is that it involves a persistent, willful attribution of God's works to evil, a kind of categorical inversion of divine truth.

Protestant Reformers, especially John Calvin, emphasized that false doctrine — claiming God commanded or endorsed something He did not — is itself a form of forbidden speech about God, echoing the Islamic concern discussed below. This remains a live issue in debates about prosperity theology and claims of direct divine revelation.

Islam's prohibitions on speech about God are among the most epistemically demanding of the three traditions. The Quran doesn't just forbid insults — it forbids unverified claims.

Surah 7:33 lists forbidden things in ascending order of gravity, culminating in: "that you associate with Allāh that for which He has not sent down authority, and that you say about Allāh that which you do not know" Quran 7:33. Classical commentators like al-Tabari (9th c.) and Ibn Kathir (14th c.) read this as a sweeping prohibition on speculative theology that outruns revelation — you can't put words in God's mouth, even well-intentioned ones.

Surah 16:116 makes the point even more concretely, targeting people who invent religious rulings and then falsely attribute them to divine authority: "And do not say about what your tongues assert of untruth, 'This is lawful and this is unlawful,' to invent falsehood about Allāh. Indeed, those who invent falsehood about Allāh will not succeed" Quran 16:116. This verse was understood by jurists as a warning against religious authorities who fabricate prohibitions or permissions without scriptural grounding.

Shirk — associating partners with God — is the gravest theological sin in Islam, and any speech that implies God has equals, children, or rivals falls under this prohibition. The Quran treats shirk as the one sin that may not be forgiven if a person dies unrepentant (Surah 4:48).

Classical Islamic jurisprudence (fiqh) developed the concept of iftira' 'ala Allah (fabricating lies against God) as a distinct legal category, and scholars like al-Ghazali (11th c.) warned that even excessive anthropomorphism in describing God — saying He has a body, emotions, or spatial location in a literal sense — risks crossing into forbidden speech.

Tanakh prohibits reviling or cursing God: “You shall not revile God” (often read as a core ban on blasphemy) Exodus 22:27. It also commands Israel not to even “make mention of the names of other gods,” banning their invocation on one’s lips Exodus 23:13. Rabbinic discussion further defines blasphemy liability and technical conditions for prohibited utterance, illustrating how Jewish law carefully circumscribes speech about the Divine Sanhedrin 66a:27 Sanhedrin 56a:11. Some Second Temple wisdom also warns against presumptuous speech before God, underscoring reverent restraint, though it’s not part of the rabbinic canon Ben Sira 7:4.

The Bible Christians read includes the prohibitions, “You shall not revile God,” rejecting cursing or insulting the divine, and “Make no mention of the names of other gods,” refusing even verbal invocation of rival deities Exodus 22:27 Exodus 23:13. Many Christian interpreters therefore treat blasphemy and unauthorized invocation of other gods’ names as forbidden speech about God, grounded in these commandments Exodus 22:27 Exodus 23:13.

The Qur’an forbids “that you say about Allah that which you do not know,” prohibiting theological assertions without knowledge Quran 7:33. It also bans inventing claims of lawful/forbidden in God’s name—declaring halal/haram without warrant—calling this a lie against Allah Quran 16:116 Quran 16:116. Within the same passage, associating others with Allah (shirk) is listed as prohibited, which extends to speech that ascribes divine partners or attributes without authority Quran 7:33. Classical exegetes tie these verses to a broader ethic of guarded, truthful God-talk.