Full Idea
Where such supernatural events are suitable to ends aim'd at by him who has the power to change the course of nature, they may be fitter to procure belief by how much more they are beyond or contrary to ordinary observation.
Gist of Idea
If miracles aim at producing belief, it is plausible that their events are very unusual
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 4.16.13)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.667
A Reaction
On this occasion there is flat disagreement with Hume, who produced a famous objection to the whole idea of miracles. Locke is struggling here, since he is defending events which are totally contrary to the rest of his epistemology.