For no age is too early or too late for the health of the soul. And to say that the season for studying philosophy has not yet come, or that it is past and gone, is like saying that the season for happiness is not yet or that it is now no more. So we must exercise ourselves in the things which bring happiness, since, if that be present, we have everything.
First believe that God is a living being immortal and blessed, according to the notion of a god indicated by the common sense of mankind. For there are gods, and the knowledge of them is manifest; but they are not such as the multitude believe. Not the man who denies the gods worshipped by the multitude, but he who affirms of the gods what the multitude believes about them is truly impious. For the utterances of the multitude about the gods are not true preconceptions but false assumptions; hence it is that the greatest evils happen to the wicked and the greatest blessings happen to the good from the hand of the gods, seeing that they are always favorable to their own good qualities and take pleasure in men like themselves.
Accustom yourself to believing that death is nothing to us, for good and evil imply the capacity for sensation, and death is deprivation of all sentience; therefore a correct understanding that death is nothing to us makes the mortality of life enjoyable, by taking away the yearning after immortality.
Epicurus – Letter to Menoeceus