I cannot find a faithful message-bearer," he wrote to his friend, the scholar Atticus. "How few are they who are able to carry a rather weighty letter without lightening it by reading.
Enjoy the blessing of strength while you have it and do not bewail it when it is gone, unless, forsooth, you believe that youth must lament the loss of infancy, or early manhood the passing of youth. Life's race-course is fixed; Nature has only a single path and that path is run but once, and to each stage of existence has been allotted its own appropriate quality; so that the weakness of childhood, the impetuosity of youth, the seriousness of middle life, the maturity of old age.. each bears some of Nature's fruit, which must be garnered in its own season.
Not to know what has been transacted in former times is to be always a child. If no use is made of the labors of past ages, the world must remain always in the infancy of knowledge.
Leisure consists in all those virtuous activities by which a man grows morally, intellectually, and spiritually. It is that which makes a life worth living.
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.