Full Idea
Those who endeavour to establish God's existence and the truth of religion by means of miracles seek to prove the obscure by what is more obscure.
Gist of Idea
Trying to prove God's existence through miracles is proving the obscure by the more obscure
Source
Baruch de Spinoza (Letters to Oldenburg [1665], 1675?)
Book Reference
Spinoza,Benedict de: 'Ethics, Improvement of Understanding, Letters', ed/tr. Elwes,R [Dover 1955], p.302
A Reaction
Nicely put. On the whole this has to be right, but one must leave open a possibility. If there is a God, and He seeks to prove Himself by a deed, are we saying this is impossible? Divine intervention might be the best explanation of something.