The gist of this letter is found in this quote:
We should strive, not to live long, but to live rightly; for to achieve long life you have need of Fate only, but for right living you need the soul.
This is the response to anyone who suggests that someone who has died before their time; and it serves as a reminder to live each day as if it were your last.
I have noticed many who deal fairly with their fellow-men, but none who deals fairly with the gods. We rail every day at Fate.
A great many things in life may seem unfair, but we should stop this line of thinking before we jump to that conclusion. It is we who assume things are unfair, when in fact, this is how the Universe operates. Is it fair that my home flooded or burned down? Is it fair that the world is warming up or cooling down too much to my liking? Is it fair that weeds exist and are in my yard? Is it fair that my knee locked up, while playing basketball, and I hyper-extended it? Is it fair that my parent dies at the age of 45 or my Marine son dies in his 20s?
Be mindful of jumping to the conclusion of 'what is fair and what is not.' The Cosmos is too complex for one person to conclude what is just and what is not. This topic comes up quite a bit in life. For my part, I like to recall the story of "The Farmer's Son: Fortune or Misfortune?" as found on my hypomnemata on wisdom.
do you consider it fairer that you should obey Nature, or that Nature should obey you? And what difference does it make how soon you depart from a place which you must depart from sooner or later?
He then explains what a good life represents, as opposed to the length of life.
rendered to itself its proper Good ... assumed control over itself ... had fulfilled all the duties of a good citizen, a good friend, a good son.
Life must be measured by the performance of good, rather than the length. A perfect circle is still perfect regardless of it's diameter.
a life of small compass can be a perfect life. Age ranks among the external things. How long I am to exist is not mine to decide, but how long I shall go on existing in my present way is in my own control.
A full life is one that has attained wisdom.
It is living until you possess wisdom. He who has attained wisdom has reached, not the furthermost, but the most important, goal.
One who lives wisely has fulfilled the measure of his creation.
for he has paid [Nature] back a better life than he has received. He has set up the pattern of a good man, showing the quality and the greatness of a good man. Had another year been added, it would merely have been like the past.
If a person lives 80 years, and does nothing but eat, sleep, drink, defecate and does hardly anything rational to improve himself or others, he is no better than an animal. But one who lives a mere two decades, and who exercises rationality and lives morally, ethically to the betterment of himself and in the service of others, we will applaud the latter and forget the former.
Ask yourself why that is.
Death visits each and all; the slayer soon follows the slain.
We all die regardless. It is how we spend the time allotted to us is what matters.