What happens when the mind is conquered and inner calm takes hold? Krishna answers: the Paramatma — the Supreme Self — settles firmly in the heart of that person. Cold does not disturb them. Heat does not disturb them. Pleasure does not send them soaring. Pain does not break them. Praise does not inflate them. Insult does not crush them.
This is not numbness or indifference. It is a stability that comes from being anchored to something deeper than circumstances. The weather of life keeps changing — seasons of comfort, seasons of hardship — but the person rooted in the Supreme Self stands steady through all of it.
An old tree by the river has seen floods and droughts. Its roots go deep enough that neither one uproots it. That depth of root is what jitatma provides — and the Paramatma is the soil it reaches.