Mathematics is an obscure field, an abstruse science, complicated and exact; yet so many have attained perfection in it that we might conclude almost anyone who seriously applied himself would achieve a measure of success.
Who does not know history's first law to be that an author must not dare to tell anything but the truth? And its second that he must make bold to tell the whole truth? That there must be no suggestion of partiality anywhere in his writings? Nor of malice?
There exists a law, not written down anywhere but inborn in our hearts; a law which comes to us not by training or custom or reading but by derivation and absorption and adoption from nature itself; a law which has come to us not from theory but from practice, not by instruction but by natural intuition. I refer to the law which lays it down that, if our lives are endangered by plots or violence or armed robbers or enemies, any and every method of protecting ourselves is morally right.
The men who administer public affairs must first of all see that everyone holds onto what is his, and that private men are never deprived of their goods by public men.
But if you should take the bond of goodwill out of the universe no house or city could stand, nor would even the tillage of the fields abide. If that statement is not clear, then you may understand how great is the power of friendship and of concord from a consideration of the results of enmity and disagreement. For what house is so strong, or what state so enduring that it cannot be utterly overthrown by animosities and division?