A man's weakness and strength, purity and impurity, are his own, and not another man's; they are brought about by himself, and not by another; and they can only be altered by himself, never by another. His condition is also his own, and not another man's. His suffering and his happiness are evolved from within. As he → thinks, so he is; as he continues to think, so he remains.  >>>

→ Positive Thinking: 5 Benefits

A strong man cannot help a weaker unless that weaker is willing to be helped, and even then the weak man must become strong of himself; he must, by his own efforts, develop the strength which he admires in another. None but himself can alter his condition.

→ 6 Mindsets of a Great Achiever

It has been usual for men to think and to say, "Many men are slaves because one is an oppressor; let us hate the oppressor." Now, however, there is amongst an increasing few a tendency to reverse this judgment, and to say, "One man is an oppressor because many are slaves; let us despise the slaves."

... All achievements, whether in the business, intellectual, or spiritual world, are the result of definitely directed thought, are governed by the same law and are of the same method; the only difference lies in the object of attainment. 

Good thoughts and actions can never produce bad results; bad thoughts and actions can never produce good results.  This is but saying that nothing can come from corn but corn, nothing from nettles but nettles.

→ Happy vs. Unhappy People: 10 Differences