GORGIS 526d-527e

The expectation of the after life reward is an incentive to practice virtue in life - Socrates' exhortations towards those
he was speaking with

And, in return for your exhortation of me, I exhort you also to take part in the great combat, which is the combat of life, and greater than every other earthly conflict. And I retort your reproach of me, and say,  that you will not be able to help yourself when the day of trial and judgment, of which I was speaking, comes upon you; you will go before the judge, the son of Aegina, and, when he has got you in his grip and is carrying you off, you will gape and your head will swim round, just as mine would in the courts of this world, and very likely some one will shamefully  box you on the ears, and put upon you any sort of insult.

Perhaps this may appear to you to be only an old wife's tale, which you will contemn. And there might be reason in your contemning such tales, if by searching we could find out anything better or truer: but now you see that you and Polus and Gorgias, who are the three wisest of the Greeks of our day, are not able to show that we ought to live any life which does not profit in another world as well as in  this. And of all that has been said, nothing remains unshaken but the saying, that to do injustice is more to be avoided than to suffer injustice, and that the reality and not the appearance of virtue is to be followed above all things, as well in public as in private life; and that when any one has been wrong in anything, he is to be chastised, and that the next best thing to a man being just is that he should become just, and be chastised and punished; also that he should avoid all flattery of himself as well as of others, of the few or of  the many: and rhetoric and any other art should be used by him, and all his actions should be done always, with a view to justice.

Follow me then, and I will lead you where you will be happy in life and after death, as the argument shows. And never mind if some one despises you as a fool, and insults you, if he has a mind; let him strike you, by Zeus, and do you be of good cheer, and do not mind the insulting blow, for you will never come to any harm in the practice of virtue, if you are a really good and true man. When we have practised virtue together, we will apply ourselves to politics, if that seems desirable, or we will advise about whatever else may seem good to us, for we shall be better able to judge then. In our present condition we ought not to give ourselves airs, for even on the most important subjects we are always changing our minds; so utterly stupid are we! Let us, then, take the argument as our guide, which has revealed to us that the best way of life is to practise justice and every virtue in life and death. This way let us go; and in this exhort all men to follow, not in the way to which you trust and in which you exhort me to follow you; for that way, Callicles, is nothing worth.