Our Lord feedeth by plain words, exerciseth by obscure. For when two persons, one godly, the other ungodly, hear the words of the Gospel, and they happen to be such that neither can understand them; one says, What He saith is true and good, but we do not understand it: the other says, It is not worth attending to. The former, in faith, knocks, yea, and, if he continue to knock, it shall be opened unto him. The latter shall hear the words in Isaiah, If ye will not believe, surely ye shall not be established1. (Isa. 7:9)
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: ut sup.