Bhagwad Gita
Chapter 6, Verse 12
तत्रैकाग्रं मनः कृत्वा यतचित्तेन्द्रियक्रियः।
उपविश्यासने युञ्ज्याद्योगमात्मविशुद्धये।।6.12।।
There, having made the mind one-pointed, with the actions of the mind and senses controlled, let him, seated on the seat, practice Yoga for the purification of the self.