Duhkheshv-Anudvignamanah

Three qualities absent, one quality present. Absent: raga (clinging to what is pleasant), bhaya (fear of what might come), and krodha (anger at what has come). Present: a mind that neither crumbles under sorrow nor gets drunk on pleasure. That person, Krishna says, is a muni of steady intellect.

The deep ocean floor stays still no matter what storms rage on the surface. Waves rise and crash, winds howl — but thirty fathoms down, there is silence. The Sthitaprajna's mind has that depth. Events reach the surface but do not reach the core.

This is not numbness. The muni feels. But feelings pass through without taking up permanent residence. Sorrow visits; it does not move in. Pleasure visits; it does not build a house.

Arjuna asked in 2.54: what does the person of steady wisdom look like? Krishna's answer here names the emotional signature — equanimity in the face of both sorrow and pleasure, and freedom from the three great disturbers: attachment, fear, and anger.

In traditional study, this section (2.55 to 2.72) is called the Sthitaprajna Prakarana. It is considered one of the most practical portions of the entire Gita.