Do not pursue what is illusory - property and position: all that is gained at the expense of your nerves decade after decade and can be confiscated in one fell night. Live with a steady superiority over life - don't be afraid of misfortune, and do not yearn after happiness; it is after all, all the same: the bitter doesn't last forever, and the sweet never fills the cup to overflowing. Alexander Solzhenitsyn

• happiness
• contentment
• stress

What man actually needs is not a tensionless state but rather the striving and struggling for a worthwhile goal, a freely chosen task. What he needs is not the discharge of tension at any cost but the call of a potential meaning waiting to be fulfilled by him. Viktor Frankl

• purpose
• goals
• stress

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

• pain
• stress

This is the source.