While practicing Yoga postures the sadhak (student) experiences certain lightness in his body. So his awareness reaches inside the body and he starts getting control over his body. When he starts practicing Pranayam he gets control over his breathing. He can feel his breath anywhere in the body. He calms down to listen to the body and slowly starts liking the peace. Now he can stop his thoughts and can meditate. This starts giving him tremendous  happiness inside. No longer he is interested  in the outside world. This leads him to reveal the truth about what is permanent and what is changing. Until now he was always interested in the changing world but now he knows where his interest lies. Without his knowledge he comes on the path of Spirituality, which leads to liberation. Every Yog sadhak gets attracted towards Patanjali Yogsutra. Please refer the next page for Patanjali Yogsutras.