swear upon

verb

verb

Formal To take an oath on someone or something.

to swear upon the Holy Writ to speak the truth
I'll swear upon that bottle to be thy true subject, for the liquor is not earthly.1610–1611 (date written), William Shakespeare, “The Tempest”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act II, scene ii]:

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