Victory breeds hatred, for the conquered is unhappy. He who has given up both victory and defeat, he, the contented, is happy.
Jayaṁ veraṁ pasavati, dukkhaṁ seti parājito; Upasanto sukhaṁ seti, hitvā jayaparājayaṁ.
Dhammapada 201
The same idea in other traditions
Depart from evil, and do good; Seek peace, and pursue it.
Blessed are the peacemakers: for they shall be called the children of God.
'Happy are we, happy live we who call nothing our own; when Mithilâ is on fire, nothing is burned that belongs to me.
One who does not frighten anyone, and who is not afraid of anyone else - says Nanak, listen, mind: call him spiritually wise.
He knows not God nor performs His worship who is not contented with his lot. Contentment maketh a man rich—tell this to the avaricious. …
And the servants of (Allah) Most Gracious are those who walk on the earth in humility, and when the ignorant address them, they say, "Peace!";
He through whom the world is not agitated, and who is not agitated by the world, who is free from joy and anger and fear and agitation, he too is dear to me.
The Master said, "With coarse rice to eat, with water to drink, and my bended arm for a pillow;—I have still joy in the midst of these things. Riches and honours acquired by unrighteousness, are to me as a floating cloud."
When the Tao prevails in the world, they send back their swift horses to (draw) the dung-carts. When the Tao is disregarded in the world, the war-horses breed in the border lands. There is no guilt greater than to sanction ambition; no calamity greater than to be discontented with one's lot; no fault greater than the wish to be getting. Therefore the sufficiency of contentment is an enduring and unchanging sufficiency.