2-15

यम् हि न व्यथयन्त्येते पुरुषम् पुरुषर्षभ ।
समदुःख सुखम् धीरम् सोऽमृतत्वाय कल्पते ॥ १५ ॥

yam hi na vyathayantyete puruSam puruSarSabha |
samaduHkha sukham dhIram so'mRtatvAya kalpate || 15 ||

पुरुषर्षभ [puruSarSabha] O best among men, यम् पुरुषम् [yam puruSam] the person whom एते [ete] these feelings of sorrow and joy न व्यथयन्ति [na vyathayanti] do not drain, समदुःख सुखम् [samaduHkha sukham] who views sorrow and joy equally, धीरम् [dhIram] who is wise and steadfast - सः [saH] such a person अमृतत्वाय कल्पते [amRtatvAya kalpate] is fit to attain liberation from downfall.

Liberation, also known as moksha, is to be free of everything that binds us. It is to realize the true nature of our Self and its complete and utter dependence on the Lord. It is a state of eternal knowledge and infinite joy.

Do your duties to attain liberation. Then those experiences do not drain you.

A wise and steadfast person treats the unavoidable sorrows of life on par with joy. He performs duties such as war without yearning for outcomes. He does it for liberation. The various experiences associated with duty do not affect or drain such a person. He alone will get liberation from downfalls- Not men like you who cannot tolerate this sorrow. In summary, the Self is eternal and all you need to do is work for liberation.

The Lord described the eternal nature of the Self and the temporary nature of the body, giving assurance that there is no need to grieve. Next, He elaborates the statement made before (in 2-11) - ‘Wise people do not grieve for the Self or the body’: