swear to

Also found in: Dictionary, Thesaurus, Idioms.
Related to swear to: swear words
See: vouch
References in classic literature ?
I'd just as soon tell you who I am, though, if you'll swear to keep mum, for I ain't no Phillips, either.
The manner of their swearing is this: they set a sheep in the midst of them, and rub it over with butter, the heads of families who are the chief in the nation lay their hands upon the head of the sheep, and swear to observe their promise.
The officers would also swear to obey military orders and orders from their leaders; they would swear to protect their weapons and never abandon them until they die.