Bhagavad Gita 6.22

Finding That, he will realize that there is no possession so precious. And once established there, no calamity can disturb him.

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

yaṃ labdhvā cāparaṃ lābhaṃ manyate nādhikaṃ tataḥ|
yasminsthito na duḥkhena guruṇāpi vicālyate||

English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).