A class on Bhagavad Gita 2.15 given by His Divine Grace A.C. Bhaktivedanta Swami Prabhupada on August 21, 1973 in London.
Bhagavad Gita 2.15
yaṁ hi na vyathayanty ete
puruṣaṁ puruṣarṣabha
sama-duḥkha-sukhaṁ dhīraṁ
so ’mṛtatvāya kalpate
O best among men [Arjuna], the person who is not disturbed by happiness and distress and is steady in both is certainly eligible for liberation.