The heart of man finds it difficult to believe that so great a treasure as the Holy Ghost is gotten by the mere hearing of faith.
 Martin Luther, Commentary on the Epistle to the Galatians (1535). copy citation

add
Author Martin Luther
Source Commentary on the Epistle to the Galatians
Topic faith heart
Date 1535
Language English
Reference
Note Translated by Theodore Graebner
Weblink http://www.gutenberg.org/files/1549/1549-h/1549-h.htm

Context

“All the same, they could not obtain a quiet conscience and peace in Christ. But the moment the Gospel of Christ touches them, certainty comes to them, and joy, and a right judgment. I have good reason for enlarging upon this point. The heart of man finds it difficult to believe that so great a treasure as the Holy Ghost is gotten by the mere hearing of faith. The hearer likes to reason like this: Forgiveness of sins, deliverance from death, the gift of the Holy Ghost, everlasting life are grand things. If you want to obtain these priceless benefits, you must engage in correspondingly great efforts.” source