Bhagwad Gita
Chapter 5, Verse 20
न प्रहृष्येत्प्रियं प्राप्य नोद्विजेत्प्राप्य चाप्रियम्।
स्थिरबुद्धिरसम्मूढो ब्रह्मविद्ब्रह्मणि स्थितः।।5.20।।
A person who neither rejoices upon achieving something pleasant nor laments upon obtaining something unpleasant, who is self-intelligent, unbewildered, and who knows the science of God, is to be understood as already situated in Transcendence.