Mahabharata 12.304.9

धारणा चैव मनसः प्राणायामश्च पार्थिवप्राणायामो हि सगुणो निर्गुणं धारणं मनः

dhāraṇā caiva manasaḥ prāṇāyāmaśca pārthivaprāṇāyāmo hi saguṇo nirguṇaṃ dhāraṇaṃ manaḥ

Our plain-language meaning of this verse is waiting for scholar review.