M. Tullius Cicero Pro C. Rabirio Perduellionis Reo Ad Quirites 30

[30] Such is not the truth, O Romans. Nor is there any one among us who exerts himself amid the dangers of the republic with virtue and glory, who is not induced to do so by the hope he entertains of receiving his reward from posterity—therefore, while there are many reasons why I think that the souls of good men are divine and undying, this is the greatest argument of all to my mind, that the more virtuous and wise each individual is, the more thoroughly does his mind look forward to the future, so as to seem, in fact, to regard nothing except what is eternal. Wherefore, I call to witness the souls of Caius Marius and of the other wise men and gallant citizens which seem to me to have emigrated from life among men to the holy habitations and sacred character of the gods, that I think it my duty to contend for their fame, and glory, and memory, no less than for the shrines and temples of my native land; and that if I had to take up arms in defence of their credit, I should take them up no less zealously than they took them up in defence of the common safety. In truth, O Romans, nature has given us but a limited space to live in, but an endless period of glory. 11
  Wherefore, if we pay due honour to those who have already died, we shall leave to ourselves a more favourable condition after death. But it O Labienus, you neglect those whom we are unable any longer to behold, do not you think that at least you ought to consult the interests of these men whom you see before you?