Difficulty, my brethren, is the nurse of greatness -- a...

Difficulty, my brethren, is the nurse of greatness -- a harsh nurse, who roughly rocks her foster-children into strength and athletic proportion. The mind grappling with great aims and wrestling with mighty ingredients, grows, by certain necessity, to their stature. Scarce anything so convinces me of the capacity of the human intellect for indefinite expansion in the different stages of its being, as this power of enlarging itself to the compass of surrounding emergencies.