Concentration, itself, is nothing but a matter of control of the attention! Learn to fix your attention on a given subject, at will, for whatever length of time you choose, and you will have learned the secret passage-way to power and plenty! This is concentration!
Napoleon HillEveryone faces defeat. It may be a stepping-stone or a stumbling block, depending on the mental attitude with which it is faced.
Napoleon HillOne of the most common causes of failure is the habit of quitting when one is overtaken by temporary defeat.
Napoleon Hill