He used to say, If I am not for myself who is for me? and being for my own self what am I? If not now when?
הוּא הָיָה אוֹמֵר, אִם אֵין אֲנִי לִי, מִי לִי. וּכְשֶׁאֲנִי לְעַצְמִי, מָה אֲנִי. וְאִם לֹא עַכְשָׁיו, אֵימָתָי:
Pirkei Avot 1:14
The same idea in other traditions
Be not hasty in thy spirit to be angry: for anger resteth in the bosom of fools.
As a solid rock is not shaken by the wind, wise people falter not amidst blame and praise.
See the brotherhood of all mankind as the highest order of Yogis; conquer your own mind, and conquer the world.
The Master said, "When the year becomes cold, then we know how the pine and the cypress are the last to lose their leaves."
O ye who believe! Fasting is prescribed to you as it was prescribed to those before you, that ye may (learn) self-restraint,-
And if any accidents whatever befall him who has gained that (foundation), he will not be overpowered by them as a mountain by the storm.
Your business is with action alone; not by any means with fruit. Let not the fruit of action be your motive (to action). Let not your attachment be (fixed) on inaction.
Eat in proportion to thy hunger; how can he give praises who scarce can breathe by reason of his gluttony? He whose stomach is full is void of wisdom. The prey is entrapped in the snare because of its greed. …