The ancient christians knew not this divinity, nor the sounder heathens this moral philosophy. For otherwise saith Augustine, They are perjured, who keeping the words, deceive the expectation of those they swear to: and otherwise saith Cicero," &c. He goeth on to confirm it at large by argument. _Rule_ IX. An oath is to be taken and interpreted strictly. Sanderson saith,[69] _Juramenti obligatio est stricti juris_; that is, _non ut excludat juris interpretationem æquitate temperatam; sed ut excludat juris interpretationem gratia corruptam_: "not as excluding an equitable interpretation, but as excluding an interpretation corrupted by partiality:" that it be a just interpretation, between the extremes of rigid, and favourable or partial; and in doubtful cases it is safer to follow the strict, than the benign or favourable sense. It is dangerous stretching and venturing too far in matters of so sacred a nature, and of such great importance as vows and oaths. _Rule_ X. In the exposition of such doubtful oaths and vows, 1. We must specially watch against self-interest or commodity, that it corrupt not our understandings. 2. And we must not take our oaths or any part of them in such a sense, as a pious, prudent stander-by that is impartial, and no whit interested in the business, cannot easily find in the words themselves.[70] _Rule_ XI. In doubtful cases the greatest danger must be most carefully avoided, and the safer side preferred: but the danger of the soul by perjury is the greatest, and therefore no bodily danger should so carefully be avoided: and therefore an oath that in the common and obvious sense seemeth unlawful should not be taken, unless there be very full evidence that it hath another sense. Sand. p. 46, _Nititur autem_, &c. This reason leaneth on that general and most useful rule, that in doubtful cases we must follow the safer side: but it is safer not to swear, where the words of the oath proposed, do seem according to the common and obvious sense of the words to contain in them something unlawful; than by a loose interpretation so to lenify them for our own ends, that we may the more securely swear them. For it is plain that such an oath may be refused without the peril of perjury; but not that it can be taken without some danger or fear. The same rule must guide us also in keeping vows.