stoicism

You have power over your mind – not outside events. Realize this, and you will find strength.
-Marcus Aurelius

To bear trials with a calm mind robs misfortune of its strength and burden.
-Seneca

In prosperity it is very easy to find a friend; but in adversity it is the most difficult of all things.
-Epictetus

If you are distressed by anything external, the pain is not due to the thing itself, but to your estimate of it; and this you have the power to revoke at any moment. -Marcus Aurelius

Live a good life. If there are gods and they are just, then they will not care how devout you have been, but will welcome you based on the virtues you have lived by. If there are gods, but unjust, then you should not want to worship them. If there are no gods, then you will be gone, but will have lived a noble life that will live on in the memories of your loved ones.
-Marcus Aurelius

We should not, like sheep, follow the herd of creatures in front of us, making our way where others go, not where we ought to go.
-Seneca

Deliberate much before saying or doing anything, for you will not have the power of recalling what is said or done.
-Epictetus

Say to yourself in the early morning: I shall meet today ungrateful, violent, treacherous, envious, uncharitable men. All of these things have come upon them through ignorance of real good and ill… I can neither be harmed by any of them, for no man will involve me in wrong, nor can I be angry with my kinsman or hate him; for we have come into the world to work together.
-Marcus Aurelius

The happiness of your life depends upon the quality of your thoughts.
-Marcus Aurelius

The man who has anticipated the coming of troubles takes away their power when they arrive.
-Seneca