Two monks live near each other at the same time. They both profess to be students. Only one, however, does anything towards disciplining his mind. One uses language and lamentations as follows : — ” They have invented a new language, which they call Greek ; you must be carefully on your guard against it ; it is the matter of all heresy. I observe in the hands of many persons a book written in that language, and which they call the New Testament. It is a book  full of daggers and poison. As to the Hebrew, my dear brethren, it is certain that whoever learns it becomes immediately a Jew.” The other monk seizes the New Testament, and applies his habits of study and of diligence to it ; and with that Bible he shakes all Europe ; he shakes the world, and, in a day, opens upon Christendom the light of thousands of years. Need I say, I mean Martin Luther? Nothing but his disciplined mind, and his habits of using that instru ment, could have led him through the thick darkness which surrounded him, to the clear light in which we see him.

(John Todd, The Student’s Manual, page 38)

He who trains his mind to go by impulses, and must wait for them, will accomplish but very little during his life. The perfection of a disciplined mind is, not to be able, on some great contingency, to rouse up its faculties, and draw out a giant strength, but to have it always ready to produce a given and an equal quantity of results in a given and equal time. This was the glory of the mind of Isaac Newton.

You may call upon your mind, today, for its highest efforts, and stretch it to the utmost in your power, and you have done yourself a kindness. The mind will be all the better for it. Tomorrow you may do it again ; and each time it will answer more readily to your calls. But remember that real discipline of mind does not so much consist in now and then making a great effort, as in having the mind so trained that it will make constant efforts. Gutta cavat lapidem, non vi, sed saepe cadendo (a water drop hollows a stone not by force, but by falling often). If you would have the discipline any thing like perfect, it must be unremitted ; the mind must be kept clear and shrewd.