आत्मौपम्येन सर्वत्र समं पश्यति योऽर्जुन ।
सुखं वा यदि वा दुःखं स योगी परमो मतः ।। ६.३२ ।।

ātmaupamyena sarvatra samaṁ paśyati yo’rjuna |
sukhaṁ vā yadi vā duḥkhaṁ sa yogī paramo mataḥ || 6.32 ||

Krishna has something more to say about the pinnacle of spiritual enlightenment:

The Yogi, who perceives the Self everywhere and alike in the event of sukha or duhkha, I consider to be excellent and supreme.

The true Yogi, he says, will see everything as his Self. It is not that he will not see the world or objects around him. The five senses will still be ceaselessly engaged in bringing in perceptions of the outside world. Neither the perception of the objects nor the role of the senses, is questioned, negated or invalidated by Self-knowledge. In fact, Self-realization becomes necessary and useful only in the context of the variety of the world, and the plurality of sense perceptions.

Equal vision (sama-darsana) has its bearing only in the context of unequal display. The world naturally evokes through senses the dual feeling of sukha and duhkha. Equal vision must be towards sukha and duhkha that arise in the mind under various conditions and situations. World interaction means generation of sukha and duhkha. Krishna says that the excellent Yogi or Knower is he who equates both sukha and duhkha with the Self, and preserves an unfailing note of uniformity towards both.

The secret of such uniformity lies in knowing the Self rightly. Sukha and duhkha are experiences of the ‘I’ or the Self. That is why everyone says “I am happy” or “I am unhappy”. What is present in happiness is the ‘I’. It is the same ‘I’ that becomes unhappy too. The entity that manifests happiness is not happiness itself. Happiness is but a condition or aspect of that fundamental entity. The Self-knower realizes that it is the ‘I am’ part that appears both as happiness and unhappiness.

That is the secret of the Knower – how he sees the Self everywhere, and regards all experiences as revelations of the same single substratum. Alikeness with the Self, becomes his very nature.