Definition
An oath taken outside the formal compulsory process of a court or official proceeding — one that a person undertakes of their own initiative, not because any legal authority has ordered or compelled it. The administering officer, if any, lacks the power to demand that the oath be taken; the swearer comes voluntarily.
The key distinction is compulsion: a voluntary oath arises from the choice of the party, not from a legal obligation to swear. It may be administered by a magistrate or officer, but one without authority to compel testimony or the swearing itself. This places voluntary oaths in contrast to judicial oaths — those required by law as part of official proceedings, testimony under subpoena, or oaths of office mandated by statute or constitution.
Common Confusion
VOLUNTARY OATH vs. EXTRAJUDICIAL OATH: The two terms are closely related and sometimes used interchangeably. Not every extrajudicial oath, however, is strictly voluntary — some oaths taken outside formal courtroom proceedings are nonetheless legally compelled by statute or regulation (oaths of office, for example). A voluntary oath is always extrajudicial, but an extrajudicial oath is not always voluntary. Researchers should check whether the historical source is using "extrajudicial" loosely to mean voluntary, or precisely to mean simply outside court.
VOLUNTARY OATH vs. AFFIRMATION: An affirmation is a solemn declaration made by persons who conscientiously object to swearing. Both voluntary oaths and affirmations can be taken outside compulsory proceedings, but they are doctrinally distinct — an affirmation substitutes for an oath; it is not a species of oath. See RELATED TERMS.
Why It Matters in Research
The practical significance of voluntary oaths has largely dissolved in modern American law, but researchers encounter the concept frequently in nineteenth-century practice materials, treatises, and English statutory sources. Several navigational points:
**Historical trap — the English statutory baseline.** Rapalje & Lawrence cites 5 & 6 Will. IV. c. 62, the False Oaths Act of 1835, which imposed criminal liability for false statements made on voluntary oaths administered under statute. Before that Act, perjury liability for voluntary oaths was uncertain in English law. A researcher reading pre-1835 English sources should not assume that a voluntary oath carried the same legal consequences as a judicial oath.
**Blackstone's framing.** Both Bouvier and Burrill cite 4 Bl. Com. 137, where Blackstone discusses false swearing in the context of oaths not covered by the perjury statutes. This is the foundational reference. Researchers tracing the doctrine of voluntary oaths back to its common-law roots should begin there, not with American cases.
**Modern relevance points.** The concept still surfaces in: (1) affidavits submitted voluntarily to agencies or officials, where the question is whether false statements trigger perjury or only false-statement statutes; (2) voluntary acknowledgments of paternity (sworn outside judicial process); and (3) notarizations and self-administered oaths in transactional practice. In each setting, the voluntariness of the oath affects which legal consequences attach to a false swearing.
**Corpus connection — Rule 603.** Modern evidence law governs the oath or affirmation requirement for witnesses at trial, a compelled and judicial setting. The voluntary oath sits outside Rule 603's domain. Researchers moving from voluntary oaths into modern evidence analysis should track this boundary carefully.
Historical Dictionary Support
All four source dictionaries converge on the same core definition: a voluntary oath is one taken in an extrajudicial matter, or before an officer without power to compel it. Bouvier and Burrill are nearly identical, both tracing to Blackstone's Commentaries (4 Bl. Com. 137). Black's adds the gloss from Brown that voluntary oaths are taken "not regularly in a court of justice," which helpfully foregrounds the courtroom/non-courtroom divide even if it slightly underdetermines the concept (some oaths taken in court proceedings can also be voluntary in character if the party chooses to swear to a supplemental matter not required by the tribunal).
Rapalje & Lawrence is the most practically useful of the four: it flags the English statutory treatment and gestures toward criminal consequences, which the other dictionaries omit. This is significant for researchers interested in the perjury dimensions of voluntary oaths — the other three dictionaries give no guidance on the consequences of falsely swearing a voluntary oath, which was the central legal problem the 1835 Act was designed to address.
What none of the historical dictionaries adequately covers is the American statutory landscape. By the late nineteenth century, many states had enacted false-swearing statutes that extended perjury-like liability to voluntary oaths administered before authorized officers (notaries, commissioners, etc.), collapsing some of the practical distinction. Researchers relying solely on these dictionary entries for American practice will miss that development.
Jurisdictional Note
American states vary significantly in how false swearing on a voluntary oath is treated. Some states assimilate it to perjury; others maintain a lesser "false swearing" or "false statement" offense; a few retain the older common-law position that perjury requires a judicial proceeding. Researchers handling historical American materials must check the applicable state statute before assuming consequences.
Encyclopedia Cross-Reference
The Law Mind Civil Procedure & Evidence Encyclopedia: Oath or Affirmation — Rule 603 (civpro_168) — for the compelled judicial oath context that defines voluntary oaths by contrast.
The Law Mind Family Law Encyclopedia: Paternity — Voluntary Acknowledgment of Paternity (family_108) — for a modern application where sworn acknowledgments are executed outside judicial proceedings.