A knower of Brahman does not get swept away when something pleasant arrives, and does not panic when something unpleasant comes. That person's intellect is steady. Delusion has no hold. They are established in Brahman.
An old tree — whether strong winds batter it, heavy rain soaks it, or harsh sun beats down — does not budge from its roots. The brahma-jnani's steadiness is like that. Neither good fortune nor bad fortune can shake them.