Bhagavad Gita 6.7

The Self of one who is self-controlled and has attained peace is equally unmoved by heat or cold, pleasure or pain, honor or dishonor.

जितात्मनः प्रशान्तस्य परमात्मा समाहितः।
शीतोष्णसुखदुःखेषु तथा मानापमानयोः॥

jitātmanaḥ praśāntasya paramātmā samāhitaḥ|
śītoṣṇasukhaduḥkheṣu tathā mānāpamānayoḥ||

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