2:15  

यं हि न व्यथयन्त्येते पुरुषं पुरुषर्षभ ।
समदुःखसुखं धीरं सोऽमृतत्वाय कल्पते ॥२- १५॥

yaM hi na wyathayantyete puruShaM puruSharShabha ।

samaduHkhasukhaM dhiiraM so'mRRitatwaaya kalpate ॥२- १५॥

Source: Automatic ITRANS Transliteration

The person whom these do not disturb, O bull among people,
Equally steadfast in contentment or suffering, they achieve immortality.

Source: Milind S. Pandit

Because the calm person, who is not afflicted by these feelings and is steady in pain and pleasure, becomes fit for immortality, O Arjuna.

Source: The Bhagavad-Gita: The Sacred Song

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.

Source: Bhagavad Gita As It Is