18.33 That Dhrti by which one through unswerving Yoga sustains the activities of the mind and the vital force and the sense-organs is said to be of the nature of Sattva. 'Yoga is worship of the Lord which forms the means for release. The meaning is that the Dhrti or fortitude by means of which one sustains the activities of the mind and other organs in the practice of Yoga (worship) until one's object is accomplished, is of the nature of Sattva.