"Three things are necessary for the salvation of man: to know what he ought to believe; to know what he ought to desire; and to know what he ought to do"
About this Quote
The subtext is a defense of moral formation against two temptations: pure intellectualism (if you just know the right ideas, you’re safe) and pure voluntarism (if you just mean well, you’re safe). Aquinas insists that the human being is a bundle of intellect, appetite, and will, and any spiritual program that ignores one will produce a warped person: correct but cruel, passionate but chaotic, dutiful but hollow.
Context sharpens the stakes. Writing in the high medieval university world, Aquinas is trying to reconcile Christian theology with Aristotelian psychology and ethics. “Know what he ought” smuggles in authority: the Church, Scripture, reason, and tradition don’t merely inform your choices; they norm them. That’s why the line still lands today. It’s a quiet provocation to modern “authenticity” culture: if your desires are treated as automatically legitimate, Aquinas replies that desire itself needs education - and that salvation, however you translate it, is inseparable from that hard, unglamorous re-training.
Quote Details
| Topic | Faith |
|---|---|
| Source | Unverified source: Collationes in decem praeceptis (Sermons on the Commandme... (Thomas Aquinas, 1273)
Evidence: Prologue (Prooemium), opening sentence. The line appears in Aquinas’s "Collationes in decem praeceptis" (a reportatio, i.e., student/assistant report, traditionally attributed to Aquinas). Latin incipit: "Tria sunt homini necessaria ad salutem: scilicet scientia credendorum, scientia desiderandor... Other candidates (2) Thomas Aquinas (Thomas Aquinas) compilation99.2% variant translation three things are necessary for the salvation of man to know what he ought to believe to know what... CliffsNotes on Adams' The Education of Henry Adams (Stanley P. Baldwin, 2007) compilation97.9% ... Thomas Aquinas wrote ( in Two Precepts of Charity ) in 1273 , “ Three things are necessary for the salvation of m... |
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Citation Formats
APA Style (7th ed.)
Aquinas, Thomas. (2026, January 13). Three things are necessary for the salvation of man: to know what he ought to believe; to know what he ought to desire; and to know what he ought to do. FixQuotes. https://fixquotes.com/quotes/three-things-are-necessary-for-the-salvation-of-34653/
Chicago Style
Aquinas, Thomas. "Three things are necessary for the salvation of man: to know what he ought to believe; to know what he ought to desire; and to know what he ought to do." FixQuotes. January 13, 2026. https://fixquotes.com/quotes/three-things-are-necessary-for-the-salvation-of-34653/.
MLA Style (9th ed.)
"Three things are necessary for the salvation of man: to know what he ought to believe; to know what he ought to desire; and to know what he ought to do." FixQuotes, 13 Jan. 2026, https://fixquotes.com/quotes/three-things-are-necessary-for-the-salvation-of-34653/. Accessed 12 Feb. 2026.













