Bhagavad Gita · 6.22

यं लब्ध्वा चापरं लाभं मन्यते नाधिकं ततः।यस्मिन्स्थितो न दुःखेन गुरुणापि विचाल्यते॥

yaṁ labdhvā chāparaṁ lābhaṁ manyate nādhikaṁ tataḥ yasmin sthito na duḥkhena guruṇāpi vichālyate

Having gained which, one considers no other gain to be greater; established in which, one is not shaken even by the heaviest sorrow —

— Bhagavad Gita 6.22

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)