Bhagavad Gita · Chapter 5: Renunciation in Action

Bhagavad Gita 5.20

na prahṛṣyetpriyaṃ prāpya nodvijetprāpya cāpriyam | sthirabuddhirasammūḍho brahmavidbrahmaṇi sthitaḥ ||

One should not rejoice on getting what is pleasant, nor be shaken on getting what is unpleasant. With steady understanding and free from delusion, the knower of Brahman rests in Brahman.

Modern context

The test of steadiness is how a person meets good news and bad news. The verse does not ask anyone to feel nothing. It warns against being carried off, against the elation that makes a person careless and the shock that makes them collapse. Both pass, and a person who knows this can enjoy what is pleasant without clutching it and face what is unpleasant without panic. Such a person is also far more useful to others in a crisis.