Bhagwad Gita
Chapter 6, Verse 2
यं संन्यासमिति प्राहुर्योगं तं विद्धि पाण्डव।
न ह्यसंन्यस्तसङ्कल्पो योगी भवति कश्चन।।6.2।।
What is called renunciation is the same as yoga, or linking oneself with the Supreme, for no one can become a yogi unless he renounces the desire for sense gratification.