Never enter a contest where victory is not up to you...

Donald's Commentary on The Handbook of Epictetus #19

You can be invincible if you never enter a contest in which victory is not under your control. Beware lest, when you see some person preferred to you in honor, or possessing great power, or otherwise enjoying high repute, you are ever carried away by the external impression, and deem him happy. For if the true nature of the good is one of the things that are under our control, there is no place for either envy or jealousy; and you yourself will not wish to be a praetor, or a senator, or a consul, but a free man. Now there is but one way that leads to this, and that is to despise the things that are not under our control.

Commentary

You can be undefeated if you only engage in contests where victory is within your power, in other words. When you see someone being honored by others or possessing great power, be cautious once again not to let your initial impression sweep you along with it, into assuming he is fortunate, but pause for thought. Don’t, in other words, allow yourself to assume that the things the majority of people crave necessarily make them fulfilled in life.