Patanjali Yoga Sutra 1.2

Yoga is the stilling of the turnings of the mind-stuff.

योगश्चित्तवृत्तिनिरोधः ॥

yogas citta-vrtti-nirodhah ||

Yoga is the stilling of the turnings of the mind-stuff.

the mind is filled with vrittis —a constant, spinning whirlpool of thought patterns, sudden emotions, perceptions, and memories. When this whirlpool spins out of control, we experience severe anxiety, endless rumination, and stress. The ultimate goal of yoga (and modern psychological mindfulness) is nirodhah : the intentional stilling of these restless fluctuations. However, there is a crucial clinical distinction. Stilling the mind means patiently training your attention so that the whirlpool slows down, and you can see reality clearly. It does not mean completely erasing your thoughts, harshly suppressing your emotions, or becoming numb to your own life.