B.G 2.15

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

yaṁ hi na vyathayantyete puruṣaṁ puruṣarṣabha। samaduḥkhasukhaṁ dhīraṁ so'mṛtatvāya kalpate ॥ 2-15॥

[यम् (yam) - whom; हि (hi) - indeed; न (na) - not; व्यथयन्ति (vyathayanti) - disturb; एते (ete) - these; पुरुषम् (puruṣam) - person; पुरुषर्षभ (puruṣarṣabha) - O best among men; समदुःखसुखम् (samaduḥkhasukham) - equanimous in pain and pleasure; धीरम् (dhīram) - one who possesses steadfast intellect, composure, courage, and self-control; सः (saḥ) - he; अमृतत्वाय (amṛtatvāya) - for immortality; कल्पते (kalpate) - is fit.;]

O best among men, the person who remains undisturbed by these, who is equanimous in both pain and pleasure is 'dhīra', i.e. one who possesses steadfast intellect, composure, courage, and self-control, and is indeed fit for immortality.

Gīta Bhāshya 2.15

The being is the one who is lying in the city, called 'puri', i.e. body. Because of the absence of bodily connection, one who is not perturbed at any point in time is specially called 'purusha'. How? By bravery, one can learn to react with equanimity towards pain and pleasure.

अतः प्रयोजनमाह यं हि इति॥ यम् एते मात्रास्पर्शा न व्यथयन्ति। पुरि शयमेव सन्तम्। शरीरसम्बन्धाभावे सर्वेषामपि व्यथाभावात् पुरुषम् इति विशेषणम्। कथं न व्यथयन्ति? समदुःखसुखत्वात्। तत्कथम्? धैर्येण ॥ १५ ॥

ataḥ prayojanamāha yaṃ hi iti॥ yam ete mātrāsparśā na vyathayanti। puri śayameva santam। śarīrasambandhābhāve sarveṣāmapi vyathābhāvāt puruṣam iti viśeṣaṇam। kathaṃ na vyathayanti? samaduḥkhasukhatvāt। tatkatham? dhairyeṇa ॥ 15 ॥

[अतः (ataḥ) - therefore; प्रयोजनम् (prayojanam) - purpose; आह (āha) - says; यं (yaṃ) - whom; हि (hi) - indeed; इति (iti) - thus; यम् (yam) - whom; एते (ete) - these; मात्रास्पर्शाः (mātrāsparśāḥ) - sense-contacts; न (na) - not; व्यथयन्ति (vyathayanti) - disturb; पुरि (puri) - in the city; शयम् (śayam) - lying; एव (eva) - indeed; सन्तम् (santam) - being; शरीरसम्बन्धाभावे (śarīrasambandhābhāve) - in the absence of body connection; सर्वेषाम् (sarveṣām) - of all; अपि (api) - even; व्यथाभावात् (vyathābhāvāt) - due to absence of disturbance; पुरुषम् (puruṣam) - man; इति (iti) - thus; विशेषणम् (viśeṣaṇam) - qualification; कथम् (katham) - how; न (na) - not; व्यथयन्ति (vyathayanti) - disturb; समदुःखसुखत्वात् (samaduḥkhasukhatvāt) - due to equanimity in pain and pleasure; तत् (tat) - that; कथम् (katham) - how; धैर्येण (dhairyeṇa) - with courage;]

Its (overcoming self-attachment) practical use is stated by 'yam hi' verse. The person referred here is the one who does not get perturbed by the contact of sensations. The being is the one who is lying in the city, called 'puri' i.e. body. Because of the absence of bodily connection, one who is not perturbed all the time is specially called 'purusha'. How can one overcome this disturbance? Having equanimity towards pain and pleasure. How? By bravery.

Gīta Tātparya 2.15

One can defeat death only by becoming 'purusha', i.e., understanding auspicious qualities of the Lord.

फलमाह। यं हीति। न केवलमव्यथामात्रेणामृतत्वं किन्तु पुरुषम्।

phalam āha। yaṁ hīti। na kevalam avyathāmātreṇāmṛtatvaṁ kintu puruṣam।

[फलम् (phalam) - fruit; आह (āha) - said; यम् (yam) - which; हि (hi) - indeed; इति (iti) - thus; न (na) - not; केवलम् (kevalam) - only; अव्यथा (avyathā) - without pain; मात्रेण (mātreṇa) - by measure; अमृतत्वम् (amṛtatvam) - immortality; किन्तु (kintu) - but; पुरुषम् (puruṣam) - man;]

The benefit (of enduring pleasure and pain with equanimity) is described in 'yam hi' verse. One cannot defeat death just by getting rid of misery. One can defeat it by becoming 'purusha'.

"पुरु ब्रह्म गुणाधिक्यात् तज्ज्ञानात्पुरुषः स्मृतः"

"puru brahma guṇādhikyāt tajjñānātpuruṣaḥ smṛtaḥ"

[पुरु (puru) - abundant; ब्रह्म (brahma) - Brahman; गुणाधिक्यात् (guṇādhikyāt) - due to the superiority of qualities; तज्ज्ञानात् (tajjñānāt) - from the knowledge of that; पुरुषः (puruṣaḥ) - man; स्मृतः (smṛtaḥ) - is remembered;]

"Brahman is called 'pura' because of increased auspicious qualities. One who has such knowledge of Brahman is called 'Purusha'".

इति प्रवृत्ते।

iti pravṛtte।

[इति (iti) - thus; प्रवृत्ते (pravṛtte) - engaged;]

–thus states the ancient text Pravrutti.

पुरुसरणात् पुरुष इत्यर्थः ॥१५॥

purusaraṇāt puruṣa ityarthaḥ ॥15॥

[पुरुसरणात् (purusaraṇāt) - one who does after the knowledge of auspicious qualities of Purusha; पुरुषः (puruṣaḥ) - is the 'purusha'; इति (iti) - thus; अर्थः (arthaḥ) - meaning;]

'Purusha' means one who goes after the knowledge of auspicious qualities of the Purusha.