Bhagavad Gita · 12.18

समः शत्रौ च मित्रे च तथा मानापमानयोः।शीतोष्णसुखदुःखेषु समः सङ्गविवर्जितः॥

samaḥ śhatrau cha mitre cha tathā mānāpamānayoḥ śhītoṣhṇa-sukha-duḥkheṣhu samaḥ saṅga-vivarjitaḥ

One who is equal toward enemy and friend, and also in honor and dishonor, equal in cold and heat, pleasure and pain, and free from attachment —

— Bhagavad Gita 12.18

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