The claim that God grounds objective morality is often defended by appeal to divine revelation: a sacred text or religious tradition states that God is the source of moral truth, and therefore God is. However, if no independent argument can show that God could ground objective morality or how he could do so, appealing to revelation alone is philosophically problematic. The trouble is not merely that revelation might be false, but that such an appeal fails as an explanation, collapses into circular reasoning, and undermines the very objectivity it aims to secure.
First, appealing to revelation without an accompanying argument is explanatorily empty. To say “God grounds morality because a revelation says so” does not explain how moral facts arise, what it means for them to be grounded, or why God is uniquely suited to play this role. Grounding is a metaphysical relation, not a label. If we cannot say whether moral truths depend on God’s will, his nature, his commands, or something else—and how that dependence works—then invoking God does no explanatory work. It becomes a placeholder rather than a theory. A grounding claim that cannot, even in principle, be unpacked is indistinguishable from simply asserting that morality exists.
Second, the appeal to revelation is epistemically circular. The authority of the revelation depends on God’s moral authority, but God’s moral authority is justified by the revelation. If we are told that God grounds morality because a text says so, and that the text is authoritative because it comes from God, then neither claim is independently supported. This is especially problematic for objective morality, which is supposed to hold regardless of anyone’s beliefs. If moral objectivity rests on accepting a particular revelation, then those who do not accept it are left without access to moral truth, which conflicts with the idea that morality is objective rather than sectarian.
Third, revelation-based grounding threatens arbitrariness unless further constraints are supplied. Without an account of why God’s decrees or nature fix moral truths, morality risks becoming contingent on divine preference. This is the force of the Euthyphro-style worry: if actions are good because God says so, morality seems arbitrary; if God says so because they are good, then morality is independent of God. Revelation alone does not resolve this dilemma. Simply stating that God grounds morality does not show that moral truths are necessary, non-arbitrary, or universally binding.
Fourth, relying on revelation shifts the problem rather than solving it. Even if a revelation claims that God grounds morality, we still must ask why that claim should be believed, interpreted one way rather than another, or taken as metaphysically informative rather than devotional. Disagreements between religions, conflicting moral teachings within texts, and the need for moral reasoning to interpret revelation all suggest that revelation presupposes moral standards rather than generates them. If moral reasoning is required to assess or interpret revelation, then morality cannot be wholly grounded in revelation without circularity.
Finally, if no argument can show that God could ground objective morality, asserting that he does so by revelation undermines rational discourse about ethics. Objective morality is typically defended as something that can be investigated, debated, and justified through reasons accessible to all rational agents. A grounding claim that rests entirely on accepting a specific revelation removes morality from shared rational inquiry and places it beyond critique. That move may preserve faith commitments, but it does so at the cost of philosophical credibility.
In sum, the problem is not that revelation is mentioned, but that revelation is asked to do work it cannot do alone. Without an independent account of how God grounds morality and why such grounding succeeds, saying that he does so “because revelation says so” is circular, explanatorily thin, and incompatible with the universality and objectivity that moral realism requires. Command is not explanation. Authority is not morality. Trying to treat them as if they are will lead many to do harm. You always lie for yourself. Nothing good can come of it. Command and authority are bad crutches for morality - they will break. They will not empower or inspire.