Bhagavad Gita 2.57 Chapter 2, Verse 57

यः सर्वत्रानभिस्नेहस्तत्तत्प्राप्य शुभाशुभम् ।
नाभिनन्दति न द्वेष्टि तस्य प्रज्ञा प्रतिष्ठिता ॥२.५७॥

yaḥ sarvatrānabhisnehastattatprāpya śubhāśubham
nābhinandati na dveṣṭi tasya prajñā pratiṣṭhitā

Meaning

One who is unattached everywhere, who neither rejoices at the good nor hates the bad that comes, has a firmly established wisdom.

Newly written by Bhajan Dhun — scholarly review in progress.

Reference: Bhagavad Gita 2.57 (Chapter 2, The Yoga of Knowledge (Sankhya Yoga), Verse 57)