Sentence:  What greater follie can there be, than for a man to torment himselfe for nothing, and that willingly and of purpose, to pray and importune him, whom he knowes to be <WSD>inexorable</WSD>; to knocke at that dore that cannot be opened? 
Meaning of the word marked with <WSD> tags:  Impossible to prevent or stop; inevitable. (from mid 16th c.)